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Borotungstic Acid (BWA)-Polyacrylamide (PAM) Solid Polymer Electrolytes for Electrochemical Capacitors
by
Yee Wei Foong
A thesis submitted in conformity with the requirements for the degree of Master of Applied Science
Department of Materials Science and Engineering University of Toronto
6.1.2 Crystallization at high content of BWA and H3PO4 (Visual inspection)...............68
vii
6.1.3 Chemical bonding analyses of BWA-PAM + H3PO4 Ternary Electrolytes (Raman analysis) ....................................................................................................70
6.1.4 Structural and chemical analyses of the precipitates (XRD and Raman analysis) .................................................................................................................72
Appendix A – Raman and FTIR Peak Assignments ....................................................................114
Appendix B – FTIR Analysis for SiWA and BWA .....................................................................118
Appendix C – Acid attack on PAM .............................................................................................119
Appendix D – Change in electrolyte thickness due to dehydration .............................................120
viii
Appendix E – Electrochemical impedance spectroscopy (EIS) analyses for the liquid cells and the solid cells ....................................................................................................................121
ix
List of Tables
Table 1: Comparison of the energy storage performance for capacitor, electrochemical capacitor
(EC), and battery [11]. .................................................................................................................... 2
Table 2: Summary of different polymer hosts for EC applications. ............................................. 17
Table 3: Compositions of BWA-PAM polymer electrolytes. ....................................................... 39
Symbol Name (unit) A Area (m2) C Capacitance (F) C(ω) Complex capacitance (F) C’ Real part of complex capacitance (F) C” Imaginary part of complex capacitance (F) d Thickness (m) E Energy (J) f Frequency (Hz) j Imaginary unit (-) P Power (W) Q Charge (C) R Resistance (Ω) or gas constant (JK-1mol-1) T Temperature (K or oC) t Time (s) U Cell voltage (V) W Weight of electrolyte films (g) Z(ω) Complex impedance (Ω) Z’ Real part of complex impedance (Ω) Z” Imaginary part of complex impedance (Ω)
Permittivity of vacuum (Fm-1) Dielectric constant (-)
Impedance phase shift (deg.) Pi (-) Conductivity (Sm-1) Angular frequency (rads-1)
1
Chapter 1 Introduction
1.1 Demand for Energy Storage
Thin, flexible, and lightweight electronics have gained interests because of recent technological
advancements [1-6]. This flexible form factor opens up a whole new dimension of design
possibilities that cannot be achieved with conventional rigid electronic components. Some
examples of flexible electronics are wearable devices, textile electronics, and flexible displays.
These flexible and wearable electronics have potentially high market values when incorporating
energy-harvesting and energy-storing capabilities.
Large scale commercialization of such devices remains challenging. One of the main limitations
is the rigidity and bulkiness of the existing energy storage devices. The bulky packaging of the
conventional energy storage devices not only adds to the deadweight of the electronic devices,
but also precludes the flexible design aspect of wearable technologies.
Thin and flexible energy storage technologies become the key enabler for the future
commercialization of most flexible electronics [7]. By replacing the conventional energy storage
devices that contain liquid electrolytes, flexible energy storage devices can also eliminate
potential electrolyte leakage, alleviate safety concerns, provide a thin and flexible form factor,
and a higher energy density to power the wearable technologies.
1.2 Energy Storage Devices
Current commercial energy storage devices are dominated by fuel cells, batteries, flywheels,
conventional capacitors, and electrochemical capacitors (ECs) [8, 9]. These devices can store
different amounts of energy (energy density) and perform at different charging-discharging rates
(power density) as represented in the Ragone chart in Figure 1 [10]. Their energy storage
performance is summarized in Table 1 [11].
Batteries and fuel cells have high energy density and are frequently used in applications that
require high energy storage capacity such as hybrid vehicles and grid energy storage [12-14].
However, they suffer from slow charging-discharging rates and a low specific power of ≤ 1 kW
kg-1 as demonstrated in Table 1. In contrast, the conventional capacitor displays a fast charging-
2
discharging rate, but has a limited energy density [15-17]. Therefore, conventional capacitors are
often used in applications that require fast energy response such as smoothing power supplies
and backup circuits for electronic devices. The goal of this thesis is to engineer an energy storage
device that can achieve both a high energy density and high power density.
Figure 1: Ragone chart for various energy storage devices [10].
Table 1: Comparison of the energy storage performance for capacitor, electrochemical
capacitor (EC), and battery [11].
Characteristics Capacitor EC Battery Specific energy (W h kg-1) < 0.1 1-10 10-100 Specific power (W kg-1) >> 10,000 500-10,000 < 1,000 Discharge time 10-6 to 10-3 1 s to 2 min 0.3-3 h Charge time 10-6 to 10-3 1 s to 2 min 1-5 h Columbic efficiency (%) ca. 100 85-98 70-85 Cycle life Almost infinite >500,000 ca. 1,000
3
1.3 Electrochemical Capacitors (ECs)
Among all energy storage devices, only the electrochemical capacitor (EC) demonstrates hybrid
properties by bridging the gap between batteries and conventional capacitors [18-21]. As shown
in Figure 1, the EC exhibits 10-100 times higher specific energy than conventional capacitors
[22, 23]. They also have longer cycle life (> 500,000 cycles) and fast charging-discharging
capability (1-120s) compared to batteries [22, 24]. Due to their excellent properties, ECs can
operate in either a stand-alone configuration, replace batteries, or form the battery-EC hybrid
systems to provide peak assist and regenerative power in vehicles, as well as to reach high
energy densities for fast-charging consumer electronics.
However, ECs have a lower energy density than batteries and require bulky packaging which
adds to their deadweight. The energy density in an EC is defined by the voltage and capacitance
in the following equation [25]:
12
(1)
where , , and .
This equation is derived by integrating the voltage change in the discharge process. Therefore, to
maximize energy, the capacitance and the operating voltage window are two key parameters.
The power of an EC is given by:
(2)
where , , and .
The current can then be represented by the equation:
(3)
where , , and .
4
By substituting equation (3) into (2) yields:
(4)
The maximum power from equation (4) can be found by taking the first differential with respect
to R and setting it to zero:
2
0 (5)
Solving equation (5) yields:
(6)
Substituting the result in (6) back into equation (4) yields the maximum power of an EC defined
by the voltage and resistance as given by equation (7) [25]:
4
(7)
where , , and .
The total resistance of the cell is a combination of resistances in the current collector, electrode
material, and the electrolyte. Typically, the electrolyte is the most resistive component in a
metallic cell. The power is also calculated by the energy released or restored during a charging-
discharging period [25]:
(8)
where , , and .
5
From the aforementioned equations, increasing the voltage improves the power density and
energy density of the ECs, while reducing the resistance prevents losing the inherently high
power density of ECs. Both the voltage and resistance are closely related to the ion movement in
the electrolyte.
A conventional EC is constructed using an electrically insulating but ionically conducting
separator film impregnated with a liquid electrolyte and sandwiched between two electrodes. The
liquid electrolyte enables fast ion movement, thus the low resistance in liquid electrolyte helps to
achieve high power density in EC devices. This thesis aims to engineer solid polymer
electrolytes for ECs to replace the conventional liquid electrolytes and improve the energy
density without losing the high power density of ECs.
6
Chapter 2 Literature Review
2.1 Solid Polymer Electrolytes (SPEs)
A typical solid polymer electrolyte (SPE) consists of a polymer host matrix, an ionic conductor,
and additives. The polymer host functions as the structural support. Due to the low intrinsic
conductivity of the polymer host, usually ionic conductors and additives are added to improve
the electrolyte performance. SPEs not only act as an ionic conductor, but also function as the
separator between the electrodes in cells or batteries. This enables SPEs to replace conventional
liquid electrolytes to eliminate the occurrence of hazardous gas or corrosive solvent leakage, as
well as remove the requirement for inert porous spacers to achieve thin, lightweight, and flexible
designs [26-29].
SPEs also offer advantages such as high mechanical strength to withstand physical deformation
to the cell. These advantages enable SPEs to have long service life and wide operating
temperature range [30-33]. SPEs are easy to process and fabrication can be full automated, and
configured into various geometries [33-35]. Various flexible solid ECs can be made using SPEs
as shown in Figure 2. Figure 2 (a) depicts a multi-cell configuration assembled by sandwiching
the polymer electrolyte between the bi-polar plates and terminal electrodes, which is favorable
for compact energy storage designs. Interdigitated finger cells in Figure 2 (b) are optimal for 2D
planar EC applications such as thin and flexible displays. Coaxial fiber ECs in Figure 2 (c) are
highly flexible to be woven within textiles, cotton, or fabric for wearable electronics and medical
monitoring devices [36].
7
Figure 2: Schematic of ECs based on SPEs in (a) flexible sandwiched cell configuration, (b)
Before Galvanostatic Test After Galvanostatic Test
Z''
(Ohm
)
Z' (Ohm)
Scan rate: 50 mV s-1
Cur
rent
(m
A c
m-2
)
Voltage (V)
Before Galvanostatic Test After Galvanostatic Test
(b)(a)
(c)
90
7.4 Summary
The optimized ternary electrolytes with composition of 75BWA-PAM + 10% H3PO4 and
85BWA-PAM + 10% Gly were demonstrated to have similar conductivity despite the different
plasticizers and BWA composition. These electrolytes can be made into solid capacitor cells that
not only demonstrated a near rectangular CV window of 1.2 V up to 1 V s-1 scan rate, but also
displayed excellent cycle life of ≥ 90% capacitance retention and remained at ca. -85o phase
angle over 10,000 charging-discharging cycles. The capacitance and rate performance of these
solid cells were not significantly compromised when replacing the liquid electrolyte with solid
polymer electrolytes. Therefore, both the 85BWA-PAM + 10% Gly and the 75BWA-PAM +
10% H3PO4 electrolytes are very promising candidates for SPE applications in fast-charging and
long-lasting ECs.
91
Chapter 8 Summary and outlook
8.1 Conclusions
In this thesis, multiple electrochemical and material characterization techniques were performed
to explore the structural and chemical bonding of the electrolyte system and the interactions
between polymer, proton conductors, and additives. A thorough analysis of the experimental
results helped to establish an understanding of the compatibility of the electrolyte materials; the
effects of additives on the electrolytes; and the effects of material properties on conductivity.
The key attributes affecting the electrolyte properties and compatibility have been identified:
water retention capability, concentration of ionic conductor, electrochemical stability window of
HPAs, and types of plasticizers. The following understandings can be summarized.
BWA-PAM Binary Electrolytes: The synthesized BWA had high purity. The BWA-
PAM binary electrolyte system had been successfully developed. High concentration of
BWA resulted in higher conductivity in PAM due to the availability of more ionic
conductors. The strong acidity of BWA can hydrolyze acrylamide groups to partially
transform PAM to PAM-co-PAA. This transformation may be beneficial as PAA is also
hygroscopic. However, the BWA-PAM electrolyte system still suffers from water
evaporation over time.
BWA-PAM + Plasticizers Ternary Electrolytes: The dehydration of BWA-PAM can
be improved by the addition of plasticizers. Two different plasticizers: acidic plasticizer
(H3PO4) and neutral plasticizer (glycerol) were investigated. The hygroscopic H3PO4 not
only helped to retain the water in the electrolyte, but also provide extra protons for
conduction. The H3PO4 can increase the conversion of PAM to PAA. At high
concentration of 85 wt% BWA, the by-product of this conversion reacted with BWA to
form NH4+-substituted BWA precipitation, which is undesirable for electrolyte
performance. In contrast, glycerol assisted the polymer electrolytes to stay well-hydrated.
The neutrality of glycerol helped to mitigate the conversion of PAM to PAA, thus
eliminating the issue of phase separation as observed in the case of H3PO4 plasticizer.
92
Solid CNT-Graphite EC Cells: The best compositions for acidic plasticizer- and neutral
plasticizer-modified BWA-PAM electrolytes were used to assemble solid cells with
CNT-graphite electrodes compared against the liquid cell counterparts. The electrolytes
modified with both plasticizers had comparable conductivity and long-term performance.
The solid cells demonstrated near rectangular CV profile of 1.2 V window and
maintained ≥ 75% discharging capacitance from 50 mV s-1 to 1 V s-1. Both cells with
H3PO4-modified and glycerol-modified electrolytes demonstrated excellent cycle life and
highly capacitive behavior by retaining ≥ 90% capacitance and ca. -85o phase angle over
the rigorous 10,000 charging-discharging cycles. Therefore, both the 85BWA-PAM +
10% Gly and the 75BWA-PAM + 10% H3PO4 ternary electrolytes are very promising
candidates for SPE applications in ECs.
93
8.2 Future work
This thesis had developed solid polymer electrolytes based on BWA-PAM system and
investigated the effects of different plasticizers on its performance. However, there are some
properties that can be examined to further enhance this electrolyte system. This research can be
carried forward by investigating the following aspects:
The cell failure is attributed to the water loss due to poor sealing technique. Better sealing
techniques such as hot press lamination can be explored to design ECs with longer
service life.
The characterizations presented in this thesis are limited to ambient temperature and 45%
relative humidity (RH). The cell performance at lower RH and various temperature
ranges can be investigated to analyze the versatility and feasibility of the cell under
different environmental conditions.
Other amorphous polymers can be explored to engineer a compatible electrolyte system
with HPAs.
Other structures and chemistries of HPAs can be investigated to further expand the
electrochemical stability window for the electrolyte systems
Crosslinking of PAM or adding nanoparticles such as nano-silica (nano-SiO2) or nano-
titanium oxide (nano-TiO2) as solid plasticizers to enhance the dimensional stability of
the electrolyte.
The compatibility of this electrolyte system with pseudocapacitive electrodes can be
investigated.
The conduction mechanism of the electrolyte systems can be characterized.
94
References
[1] L. Dong, C. Xu, Y. Li, Z. H. Huang, F. Kang, Q. H. Yang, et al., "Flexible electrodes and supercapacitors for wearable energy storage: a review by category," Journal of Materials Chemistry A, vol. 4, pp. 4659-4685, 2016.
[2] Z. Wang, W. Zhang, X. Li, and L. Gao, "Recent progress in flexible energy storage materials for lithium-ion batteries and electrochemical capacitors: A review," Journal of Materials Research, vol. 31, pp. 1648-1664, 2016.
[3] F. R. Fan, W. Tang, and Z. L. Wang, "Flexible Nanogenerators for Energy Harvesting and Self‐Powered Electronics," Advanced Materials, vol. 28, pp. 4283-4305, 2016.
[4] N. Yu, H. Yin, W. Zhang, Y. Liu, Z. Tang, and M. Q. Zhu, "High‐Performance Fiber‐Shaped All‐Solid‐State Asymmetric Supercapacitors Based on Ultrathin MnO2 Nanosheet/Carbon Fiber Cathodes for Wearable Electronics," Advanced Energy Materials, vol. 6, pp. 1-9, 2016.
[5] Y. Yang, Q. Huang, L. Niu, D. Wang, C. Yan, Y. She, et al., "Waterproof, Ultrahigh Areal‐Capacitance, Wearable Supercapacitor Fabrics," Advanced Materials, vol. 29, pp. 1-9, 2017.
[6] X. Pu, L. Li, M. Liu, C. Jiang, C. Du, Z. Zhao, et al., "Wearable self‐charging power textile based on flexible yarn supercapacitors and fabric nanogenerators," Advanced Materials, vol. 28, pp. 98-105, 2016.
[7] X. Lu, M. Yu, G. Wang, Y. Tong, and Y. Li, "Flexible solid-state supercapacitors: design, fabrication and applications," Energy & Environmental Science, vol. 7, pp. 2160-2181, 2014.
[8] M. Winter and R. J. Brodd, "What are batteries, fuel cells, and supercapacitors?," vol. 104, ed. Chem. Rev.: ACS Publications, 2004, pp. 4245-4270.
[9] R. Kötz and M. Carlen, "Principles and applications of electrochemical capacitors," Electrochimica Acta, vol. 45, pp. 2483-2498, 2000.
[10] Y. Zeng, M. Yu, Y. Meng, P. Fang, X. Lu, and Y. Tong, "Iron‐based supercapacitor electrodes: advances and challenges," Advanced Energy Materials, vol. 6, pp. 1-17, 2016.
[11] A. González, E. Goikolea, J. A. Barrena, and R. Mysyk, "Review on supercapacitors: technologies and materials," Renewable and Sustainable Energy Reviews, vol. 58, pp. 1189-1206, 2016.
[12] F. Schipper and D. Aurbach, "A brief review: Past, present and future of lithium ion batteries," Russian Journal of Electrochemistry, vol. 52, pp. 1095-1121, 2016.
95
[13] J. Jaguemont, L. Boulon, and Y. Dubé, "A comprehensive review of lithium-ion batteries used in hybrid and electric vehicles at cold temperatures," Applied Energy, vol. 164, pp. 99-114, 2016.
[14] A. Chu and P. Braatz, "Comparison of commercial supercapacitors and high-power lithium-ion batteries for power-assist applications in hybrid electric vehicles: I. Initial characterization," Journal of power sources, vol. 112, pp. 236-246, 2002.
[15] C. Emmenegger, P. Mauron, P. Sudan, P. Wenger, V. Hermann, R. Gallay, et al., "Investigation of electrochemical double-layer (ECDL) capacitors electrodes based on carbon nanotubes and activated carbon materials," Journal of Power Sources, vol. 124, pp. 321-329, 2003.
[16] H. Douglas and P. Pillay, "Sizing ultracapacitors for hybrid electric vehicles," in Industrial Electronics Society, 2005. IECON 2005. 31st Annual Conference of IEEE, 2005, p. 6.
[17] M. Jayalakshmi and K. Balasubramanian, "Simple capacitors to supercapacitors-an overview," Int. J. Electrochem. Sci, vol. 3, pp. 1196-1217, 2008.
[18] Z. S. Wu, D. W. Wang, W. Ren, J. Zhao, G. Zhou, F. Li, et al., "Anchoring hydrous RuO2 on graphene sheets for high‐performance electrochemical capacitors," Advanced Functional Materials, vol. 20, pp. 3595-3602, 2010.
[19] P. Sharma and T. Bhatti, "A review on electrochemical double-layer capacitors," Energy Conversion and Management, vol. 51, pp. 2901-2912, 2010.
[20] P. Simon and Y. Gogotsi, "Materials for electrochemical capacitors," Nature materials, vol. 7, pp. 845-854, 2008.
[21] I. Hadjipaschalis, A. Poullikkas, and V. Efthimiou, "Overview of current and future energy storage technologies for electric power applications," Renewable and sustainable energy reviews, vol. 13, pp. 1513-1522, 2009.
[22] Y. Zhang, H. Feng, X. Wu, L. Wang, A. Zhang, T. Xia, et al., "Progress of electrochemical capacitor electrode materials: A review," International journal of hydrogen energy, vol. 34, pp. 4889-4899, 2009.
[23] S. Sarangapani, B. Tilak, and C. P. Chen, "Materials for electrochemical capacitors theoretical and experimental constraints," Journal of the Electrochemical Society, vol. 143, pp. 3791-3799, 1996.
[24] Y. Wang, Y. Song, and Y. Xia, "Electrochemical capacitors: mechanism, materials, systems, characterization and applications," Chemical Society Reviews, vol. 45, pp. 5925-5950, 2016.
[25] A. Lewandowski and M. Galinski, "Practical and theoretical limits for electrochemical double-layer capacitors," Journal of Power Sources, vol. 173, pp. 822-828, 2007.
96
[26] S. Ramesh and L. C. Wen, "Investigation on the effects of addition of SiO2 nanoparticles on ionic conductivity, FTIR, and thermal properties of nanocomposite PMMA–LiCF3SO3–SiO2," Ionics, vol. 16, pp. 255-262, 2010.
[27] S. Ramesh, C. W. Liew, E. Morris, and R. Durairaj, "Effect of PVC on ionic conductivity, crystallographic structural, morphological and thermal characterizations in PMMA–PVC blend-based polymer electrolytes," Thermochimica Acta, vol. 511, pp. 140-146, 2010.
[28] C. W. Liew, R. Durairaj, and S. Ramesh, "Rheological Studies of PMMA–PVC Based Polymer Blend Electrolytes with LiTFSI as Doping Salt," PloS one, vol. 9, p. e102815, 2014.
[29] S. R. Raghavan, M. W. Riley, P. S. Fedkiw, and S. A. Khan, "Composite polymer electrolytes based on poly (ethylene glycol) and hydrophobic fumed silica: dynamic rheology and microstructure," Chemistry of materials, vol. 10, pp. 244-251, 1998.
[30] J. Adebahr, N. Byrne, M. Forsyth, D. MacFarlane, and P. Jacobsson, "Enhancement of ion dynamics in PMMA-based gels with addition of TiO2 nano-particles," Electrochimica acta, vol. 48, pp. 2099-2103, 2003.
[31] I. Nicotera, L. Coppola, C. Oliviero, M. Castriota, and E. Cazzanelli, "Investigation of ionic conduction and mechanical properties of PMMA–PVdF blend-based polymer electrolytes," Solid State Ionics, vol. 177, pp. 581-588, 2006.
[32] S. Rajendran and T. Uma, "Lithium ion conduction in PVC–LiBF4 electrolytes gelled with PMMA," Journal of power sources, vol. 88, pp. 282-285, 2000.
[33] K. S. Ngai, S. Ramesh, K. Ramesh, and J. C. Juan, "A review of polymer electrolytes: fundamental, approaches and applications," Ionics, vol. 22, pp. 1259-1279, 2016.
[34] S. Ramesh, C.-W. Liew, and K. Ramesh, "Evaluation and investigation on the effect of ionic liquid onto PMMA-PVC gel polymer blend electrolytes," Journal of Non-Crystalline Solids, vol. 357, pp. 2132-2138, 2011.
[35] S. Ramesh, T. Winie, and A. Arof, "Investigation of mechanical properties of polyvinyl chloride–polyethylene oxide (PVC–PEO) based polymer electrolytes for lithium polymer cells," European polymer journal, vol. 43, pp. 1963-1968, 2007.
[36] Q. Huang, D. Wang, and Z. Zheng, "Textile‐Based Electrochemical Energy Storage Devices," Advanced Energy Materials, 2016.
[37] H. Gao and K. Lian, "Proton-conducting polymer electrolytes and their applications in solid supercapacitors: a review," RSC Advances, vol. 4, pp. 33091-33113, 2014.
[38] A. Lewandowski, A. Olejniczak, M. Galinski, and I. Stepniak, "Performance of carbon–carbon supercapacitors based on organic, aqueous and ionic liquid electrolytes," Journal of Power Sources, vol. 195, pp. 5814-5819, 2010.
97
[39] C. Wessells, R. A. Huggins, and Y. Cui, "Recent results on aqueous electrolyte cells," Journal of Power Sources, vol. 196, pp. 2884-2888, 2011.
[40] L. Suo, O. Borodin, T. Gao, M. Olguin, J. Ho, X. Fan, et al., "“Water-in-salt” electrolyte enables high-voltage aqueous lithium-ion chemistries," Science, vol. 350, pp. 938-943, 2015.
[41] C. Wessells, R. Ruffο, R. A. Huggins, and Y. Cui, "Investigations of the electrochemical stability of aqueous electrolytes for lithium battery applications," Electrochemical and Solid-State Letters, vol. 13, pp. A59-A61, 2010.
[42] W. Li, D. Chen, Z. Li, Y. Shi, Y. Wan, G. Wang, et al., "Nitrogen-containing carbon spheres with very large uniform mesopores: the superior electrode materials for EDLC in organic electrolyte," Carbon, vol. 45, pp. 1757-1763, 2007.
[43] J. Read, "Ether-based electrolytes for the lithium/oxygen organic electrolyte battery," Journal of The Electrochemical Society, vol. 153, pp. A96-A100, 2006.
[44] P. Azaïs, L. Duclaux, P. Florian, D. Massiot, M.-A. Lillo-Rodenas, A. Linares-Solano, et al., "Causes of supercapacitors ageing in organic electrolyte," Journal of power sources, vol. 171, pp. 1046-1053, 2007.
[45] V. Khomenko, E. Raymundo-Piñero, and F. Béguin, "High-energy density graphite/AC capacitor in organic electrolyte," Journal of Power Sources, vol. 177, pp. 643-651, 2008.
[46] W. Y. Tsai, R. Lin, S. Murali, L. L. Zhang, J. K. McDonough, R. S. Ruoff, et al., "Outstanding performance of activated graphene based supercapacitors in ionic liquid electrolyte from −50 to 80oC," Nano Energy, vol. 2, pp. 403-411, 2013.
[47] A. B. McEwen, H. L. Ngo, K. LeCompte, and J. L. Goldman, "Electrochemical properties of imidazolium salt electrolytes for electrochemical capacitor applications," Journal of the Electrochemical Society, vol. 146, pp. 1687-1695, 1999.
[48] F. Wu, N. Zhu, Y. Bai, L. Liu, H. Zhou, and C. Wu, "Highly Safe Ionic Liquid Electrolytes for Sodium-Ion Battery: Wide Electrochemical Window and Good Thermal Stability," ACS Applied Materials & Interfaces, vol. 8, pp. 21381-21386, 2016.
[49] M. C. Buzzeo, C. Hardacre, and R. G. Compton, "Extended electrochemical windows made accessible by room temperature ionic liquid/organic solvent electrolyte systems," ChemPhysChem, vol. 7, pp. 176-180, 2006.
[50] M. Armand, F. Endres, D. R. MacFarlane, H. Ohno, and B. Scrosati, "Ionic-liquid materials for the electrochemical challenges of the future," Nature materials, vol. 8, pp. 621-629, 2009.
[51] Z. Lei, Z. Liu, H. Wang, X. Sun, L. Lu, and X. Zhao, "A high-energy-density supercapacitor with graphene–CMK-5 as the electrode and ionic liquid as the electrolyte," Journal of Materials Chemistry A, vol. 1, pp. 2313-2321, 2013.
98
[52] T. Abdallah, D. Lemordant, and B. Claude-Montigny, "Are room temperature ionic liquids able to improve the safety of supercapacitors organic electrolytes without degrading the performances?," Journal of power sources, vol. 201, pp. 353-359, 2012.
[53] W. J. Cho, C. G. Yeom, B. C. Kim, K. M. Kim, J. M. Ko, and K. H. Yu, "Supercapacitive properties of activated carbon electrode in organic electrolytes containing single-and double-cationic liquid salts," Electrochimica Acta, vol. 89, pp. 807-813, 2013.
[54] G. Pandey, Y. Kumar, and S. Hashmi, "Ionic liquid incorporated polymer electrolytes for supercapacitor application," 2010.
[55] M. Galiński, A. Lewandowski, and I. Stępniak, "Ionic liquids as electrolytes," Electrochimica Acta, vol. 51, pp. 5567-5580, 2006.
[56] P. Kurzweil and M. Chwistek, "Electrochemical stability of organic electrolytes in supercapacitors: Spectroscopy and gas analysis of decomposition products," Journal of Power Sources, vol. 176, pp. 555-567, 2008.
[57] M. E. Tuckerman, A. Chandra, and D. Marx, "Structure and dynamics of OH- (aq)," Accounts of chemical research, vol. 39, pp. 151-158, 2006.
[58] M. Mokhtar, E. Majlan, M. Talib, A. Ahmad, S. Tasirin, and W. Daud, "A short review on alkaline solid polymer electrolyte based on polyvinyl alcohol (PVA) as polymer electrolyte for electrochemical devices applications," International Journal of Applied Engineering Research, vol. 11, pp. 10009-10015, 2016.
[59] C. C. Yang, S. T. Hsu, and W. C. Chien, "All solid-state electric double-layer capacitors based on alkaline polyvinyl alcohol polymer electrolytes," Journal of power sources, vol. 152, pp. 303-310, 2005.
[60] G. Ma, J. Li, K. Sun, H. Peng, J. Mu, and Z. Lei, "High performance solid-state supercapacitor with PVA–KOH–K3[Fe(CN)6] gel polymer as electrolyte and separator," Journal of Power Sources, vol. 256, pp. 281-287, 2014.
[61] C. Zhong, Y. Deng, W. Hu, J. Qiao, L. Zhang, and J. Zhang, "A review of electrolyte materials and compositions for electrochemical supercapacitors," Chemical Society Reviews, vol. 44, pp. 7484-7539, 2015.
[62] S. T. Vindt and E. M. Skou, "The buffer effect in neutral electrolyte supercapacitors," Applied Physics A, vol. 122, pp. 1-6, Feb 2016.
[63] L. L. Zhang and X. Zhao, "Carbon-based materials as supercapacitor electrodes," Chemical Society Reviews, vol. 38, pp. 2520-2531, 2009.
[64] H. Ji, X. Zhao, Z. Qiao, J. Jung, Y. Zhu, Y. Lu, et al., "Capacitance of carbon-based electrical double-layer capacitors," Nature communications, vol. 5, 2014.
[65] B. E. Conway, Electrochemical supercapacitors: scientific fundamentals and technological applications: Springer Science & Business Media, 2013.
99
[66] R. Agrawal, M. Beidaghi, W. Chen, and C. Wang, "Carbon microelectromechanical systems (C-MEMS) based microsupercapacitors," in SPIE Sensing Technology+ Applications, 2015, pp. 94930C-94930C-7.
[67] G. Bajwa, "Nanocarbon/Polyoxometalate Composite Electrodes for Electrochemical Capacitors," MASc, Materials Science and Engineering, University of Toronto, 2012.
[68] J. P. Zheng, "Ruthenium Oxide‐Carbon Composite Electrodes for Electrochemical Capacitors," Electrochemical and Solid-State Letters, vol. 2, pp. 359-361, 1999.
[69] I. H. Kim and K. B. Kim, "Electrochemical characterization of hydrous ruthenium oxide thin-film electrodes for electrochemical capacitor applications," Journal of The Electrochemical Society, vol. 153, pp. A383-A389, 2006.
[70] V. Khomenko, E. Frackowiak, and F. Beguin, "Determination of the specific capacitance of conducting polymer/nanotubes composite electrodes using different cell configurations," Electrochimica Acta, vol. 50, pp. 2499-2506, 2005.
[71] Y. Huang, H. Li, Z. Wang, M. Zhu, Z. Pei, Q. Xue, et al., "Nanostructured Polypyrrole as a flexible electrode material of supercapacitor," Nano Energy, vol. 22, pp. 422-438, 2016.
[72] G. A. Snook, P. Kao, and A. S. Best, "Conducting-polymer-based supercapacitor devices and electrodes," Journal of Power Sources, vol. 196, pp. 1-12, 2011.
[73] S. W. Lee, J. Kim, S. Chen, P. T. Hammond, and Y. Shao-Horn, "Carbon nanotube/manganese oxide ultrathin film electrodes for electrochemical capacitors," ACS nano, vol. 4, pp. 3889-3896, 2010.
[74] G. X. Wang, B. L. Zhang, Z. L. Yu, and M. Z. Qu, "Manganese oxide/MWNTs composite electrodes for supercapacitors," Solid State Ionics, vol. 176, pp. 1169-1174, 2005.
[75] Q. Tian and K. Lian, "In situ characterization of heteropolyacid based electrochemical capacitors," Electrochemical and Solid-State Letters, vol. 13, pp. A4-A6, 2010.
[76] C. Zhan and D. E. Jiang, "Understanding the pseudocapacitance of RuO2 from joint density functional theory," Journal of Physics: Condensed Matter, vol. 28, p. 464004, 2016.
[77] N. Jabeen, Q. Xia, S. V. Savilov, S. M. Aldoshin, Y. Yu, and H. Xia, "Enhanced Pseudocapacitive Performance of α-MnO2 by Cation Preinsertion," ACS Applied Materials & Interfaces, vol. 8, pp. 33732-33740, 2016.
[78] D. Gu, C. Ding, Y. Qin, H. Jiang, L. Wang, and L. Shen, "Behavior of electrical charge storage/release in polyaniline electrodes of symmetric supercapacitor," Electrochimica Acta, 2017.
[79] N. Agmon, "The grotthuss mechanism," Chemical Physics Letters, vol. 244, pp. 456-462, 1995.
100
[80] D. T. Chin and H. H. Chang, "On the conductivity of phosphoric acid electrolyte," Journal of applied electrochemistry, vol. 19, pp. 95-99, 1989.
[81] L. Vilčiauskas, M. E. Tuckerman, G. Bester, S. J. Paddison, and K. D. Kreuer, "The mechanism of proton conduction in phosphoric acid," Nature chemistry, vol. 4, pp. 461-466, 2012.
[82] D. Marx, "Proton Transfer 200 Years after von Grotthuss: Insights from Ab Initio Simulations," ChemPhysChem, vol. 8, pp. 209-210, 2007.
[83] K. Kreuer, "Fast proton conductivity: A phenomenon between the solid and the liquid state?," Solid State Ionics, vol. 94, pp. 55-62, 1997.
[84] A. Chernyshev and S. Cukierman, "Thermodynamic View of Activation Energies of Proton Transfer in Various Gramicidin A Channels," Biophysical Journal, vol. 82, pp. 182-192, 2002/01/01/ 2002.
[85] X. Tong, X. Wu, Q. Wu, W. Zhu, F. Cao, and W. Yan, "Pentadecatungstotrivanadodiphosphoric heteropoly acid with Dawson structure: Synthesis, conductivity and conductive mechanism," Dalton Transactions, vol. 41, pp. 9893-9896, 2012.
[86] H. Cai, T. Huang, Q. Wu, and W. Yan, "Synthesis and conduction mechanism of high proton conductor H6SiW10V2O40⋅14H2O," Functional Materials Letters, vol. 9, p. 1650048, 2016.
[87] K. D. Kreuer, A. Rabenau, and W. Weppner, "Vehicle mechanism, a new model for the interpretation of the conductivity of fast proton conductors," Angewandte Chemie International Edition in English, vol. 21, pp. 208-209, 1982.
[88] K.-D. Kreuer, "Proton conductivity: materials and applications," Chemistry of Materials, vol. 8, pp. 610-641, 1996.
[89] H. Cai, X. Wu, Q. Wu, and W. Yan, "Synthesis and high proton conductive performance of a quaternary vanadomolybdotungstosilicic heteropoly acid," Dalton Transactions, vol. 45, pp. 14238-14242, 2016.
[90] M. Armand, "Polymers with ionic conductivity," Advanced Materials, vol. 2, pp. 278-286, 1990.
[91] M. A. Ratner and D. F. Shriver, "Ion transport in solvent-free polymers," Chemical Reviews, vol. 88, pp. 109-124, 1988.
[92] K. Murata, "An overview of the research and development of solid polymer electrolyte batteries," Electrochimica Acta, vol. 40, pp. 2177-2184, 1995.
[93] P. V. Wright, "Electrical conductivity in ionic complexes of poly (ethylene oxide)," Polymer International, vol. 7, pp. 319-327, 1975.
101
[94] P. V. Wright, "Polymer electrolytes—the early days," Electrochimica Acta, vol. 43, pp. 1137-1143, 1998.
[95] W. H. Meyer, "Polymer electrolytes for lithium‐ion batteries," Advanced materials, vol. 10, pp. 439-448, 1998.
[96] S. J. Osborn, M. K. Hassan, G. M. Divoux, D. W. Rhoades, K. A. Mauritz, and R. B. Moore, "Glass transition temperature of perfluorosulfonic acid ionomers," Macromolecules, vol. 40, pp. 3886-3890, 2007.
[97] J. T. Hinatsu, M. Mizuhata, and H. Takenaka, "Water uptake of perfluorosulfonic acid membranes from liquid water and water vapor," Journal of the Electrochemical Society, vol. 141, pp. 1493-1498, 1994.
[98] L. Liu, W. Chen, and Y. Li, "An overview of the proton conductivity of nafion membranes through a statistical analysis," Journal of Membrane Science, vol. 504, pp. 1-9, 2016.
[99] R. Kuwertz, C. Kirstein, T. Turek, and U. Kunz, "Influence of acid pretreatment on ionic conductivity of Nafion® membranes," Journal of Membrane Science, vol. 500, pp. 225-235, 2016.
[100] M. Schalenbach, W. Lueke, W. Lehnert, and D. Stolten, "The influence of water channel geometry and proton mobility on the conductivity of Nafion®," Electrochimica Acta, vol. 214, pp. 362-369, 2016.
[101] S. Slade, S. Campbell, T. Ralph, and F. Walsh, "Ionic conductivity of an extruded Nafion 1100 EW series of membranes," Journal of the Electrochemical Society, vol. 149, pp. A1556-A1564, 2002.
[102] M. Maréchal, J. L. Souquet, J. Guindet, and J. Y. Sanchez, "Solvation of sulphonic acid groups in Nafion® membranes from accurate conductivity measurements," Electrochemistry communications, vol. 9, pp. 1023-1028, 2007.
[103] Y. Yin, Z. Li, X. Yang, L. Cao, C. Wang, B. Zhang, et al., "Enhanced proton conductivity of Nafion composite membrane by incorporating phosphoric acid-loaded covalent organic framework," Journal of Power Sources, vol. 332, pp. 265-273, 2016.
[104] L. G. Boutsika, A. Enotiadis, I. Nicotera, C. Simari, G. Charalambopoulou, E. P. Giannelis, et al., "Nafion® nanocomposite membranes with enhanced properties at high temperature and low humidity environments," International Journal of Hydrogen Energy, vol. 41, pp. 22406-22414, 2016.
[105] F. A. Zakil, S. K. Kamarudin, and S. Basri, "Modified Nafion membranes for direct alcohol fuel cells: An overview," Renewable and Sustainable Energy Reviews, vol. 65, pp. 841-852, 2016.
102
[106] M. G. Hosseini and E. Shahryari, "Fabrication of novel solid-state supercapacitor using a Nafion polymer membrane with graphene oxide/multiwalled carbon nanotube/polyaniline," Journal of Solid State Electrochemistry, pp. 1-16, 2017.
[107] H. Yang, W. Lee, B. Choi, and W. Kim, "Preparation of Nafion/Pt-containing TiO2/graphene oxide composite membranes for self-humidifying proton exchange membrane fuel cell," Journal of Membrane Science, vol. 504, pp. 20-28, 2016.
[108] J. H. Chang, J. H. Park, G. G. Park, C. S. Kim, and O. O. Park, "Proton-conducting composite membranes derived from sulfonated hydrocarbon and inorganic materials," Journal of Power Sources, vol. 124, pp. 18-25, 2003.
[109] R. C. Greaves, S. P. Bond, and W. R. McWhinnie, "Conductivity studies on modified laponites," Polyhedron, vol. 14, pp. 3635-3639, 1995.
[110] C. Felice and D. Qu, "Optimization of the Synthesis of Nafion− Montmorillonite Nanocomposite Membranes for Fuel Cell Applications through Statistical Design-of-Experiment," Industrial & Engineering Chemistry Research, vol. 50, pp. 721-727, 2010.
[111] S. J. Lee, N. Muthuchamy, A. I. Gopalan, and K. P. Lee, "New Nafion/Conducting Polymer Composite for Membrane Application," 2016.
[112] C. O. Baker, X. Huang, W. Nelson, and R. B. Kaner, "Polyaniline nanofibers: broadening applications for conducting polymers," Chemical Society Reviews, vol. 46, pp. 1510-1525, 2017.
[113] J. Jalili, S. Borsacchi, and V. Tricoli, "Proton conducting membranes in fully anhydrous conditions at elevated temperature: Effect of Nitrilotris (methylenephosphonic acid) incorporation into Nafion-and poly (styrenesulfonic acid)," Journal of Membrane Science, vol. 469, pp. 162-173, 2014.
[114] H. S. Thiam, M. Y. Chia, Q. R. Cheah, C. C. H. Koo, S. O. Lai, and K. C. Chong, "Proton conductivity and methanol permeability of Nafion-SiO2/SiWA composite membranes," in AIP Conference Proceedings, 2017, p. 020007.
[115] H. Zhang, H. Huang, and P. K. Shen, "Methanol-blocking Nafion composite membranes fabricated by layer-by-layer self-assembly for direct methanol fuel cells," international journal of hydrogen energy, vol. 37, pp. 6875-6879, 2012.
[116] Y. Hu, X. Li, L. Yan, and B. Yue, "Improving the Overall Characteristics of Proton Exchange Membranes via Nanophase Separation Technologies: A Progress Review," Fuel Cells, 2017.
[117] H. Gao, H. Wu, and K. Lian, "A comparative study of polymer electrolytes for ultrahigh rate applications," Electrochemistry Communications, vol. 17, pp. 48-51, 2012.
[118] Y. Chang and C. Bae, "Acidity Effect on Proton Conductivity of Hydrocarbon-Based Ionomers," ECS Transactions, vol. 33, pp. 735-741, 2010.
103
[119] Z. Wei, S. He, X. Liu, J. Qiao, J. Lin, and L. Zhang, "A novel environment-friendly route to prepare proton exchange membranes for direct methanol fuel cells," Polymer, vol. 54, pp. 1243-1250, 2013.
[120] M. J. Parnian, S. Rowshanzamir, and F. Gashoul, "Comprehensive investigation of physicochemical and electrochemical properties of sulfonated poly (ether ether ketone) membranes with different degrees of sulfonation for proton exchange membrane fuel cell applications," Energy, vol. 125, pp. 614-628, 2017.
[121] S. Qu, Y. Sun, and J. Li, "Sulfonate poly (ether ether ketone) incorporated with ammonium ionic liquids for proton exchange membrane fuel cell," Ionics, vol. 23, pp. 1607-1611, 2017.
[122] M. J. Parnian, F. Gashoul, and S. Rowshanzamir, "Studies on the SPEEK membrane with low degree of sulfonation as a stable proton exchange membrane for fuel cell applications," Iranian Journal of Hydrogen & Fuel Cell, vol. 3, pp. 221-232, 2017.
[123] L. Zhao, F. Li, Y. Guo, Y. Dong, J. Liu, Y. Wang, et al., "SPEEK/PVDF binary membrane as an alternative proton-exchange membrane in vanadium redox flow battery application," High Performance Polymers, vol. 29, pp. 127-132, 2017.
[124] W. Xu, Y. Zhang, G. Yang, X. Yu, J. Liu, and Z. Jiang, "ZnPc-MWCNT/sulfonated poly (ether ether ketone) composites for high-k and electrical energy storage applications," IEEE Transactions on Dielectrics and Electrical Insulation, vol. 24, pp. 720-726, 2017.
[125] S. Y. Lee, H. S. Woo, J. M. Song, J. Y. Sohn, and J. Shin, "Preparation of cross‐linked SPEEK‐zirconium phosphate hybrid membranes by electron beam irradiation," Polymer Composites, 2016.
[126] F. Fuertges and A. Abuchowski, "The clinical efficacy of poly (ethylene glycol)-modified proteins," Journal of controlled release, vol. 11, pp. 139-148, 1990.
[127] M. Armand, "The history of polymer electrolytes," Solid State Ionics, vol. 69, pp. 309-319, 1994.
[128] M. Armand, "Polymer solid electrolytes-an overview," Solid State Ionics, vol. 9, pp. 745-754, 1983.
[129] N. Vijaya, S. Selvasekarapandian, G. Hirankumar, S. Karthikeyan, H. Nithya, C. Ramya, et al., "Structural, vibrational, thermal, and conductivity studies on proton-conducting polymer electrolyte based on poly (N-vinylpyrrolidone)," Ionics, vol. 18, pp. 91-99, 2012.
[130] M. Ravi, K. K. Kumar, V. M. Mohan, and V. N. Rao, "Effect of nano TiO2 filler on the structural and electrical properties of PVP based polymer electrolyte films," Polymer Testing, vol. 33, pp. 152-160, 2014.
104
[131] K. N. Kumar, T. Sreekanth, M. J. Reddy, and U. S. Rao, "Study of transport and electrochemical cell characteristics of PVP: NaClO3 polymer electrolyte system," Journal of power sources, vol. 101, pp. 130-133, 2001.
[132] M. J. Reddy, T. Sreekanth, M. Chandrashekar, and U. S. Rao, "Ion transport and electrochemical cell characteristic studies of a new (PVP1NaNO3) polymer electrolyte system," Journal of materials science, vol. 35, pp. 2841-2845, 2000.
[133] N. Vijaya, S. Selvasekarapandian, H. Nithya, and C. Sanjeeviraja, "Proton Conducting Polymer Electrolyte based on Poly (N-vinyl pyrrolidone) Doped with Ammonium Iodide," Int. J. Electroactive Mater, vol. 3, pp. 20-27, 2015.
[134] A. A. De Queiroz, D. A. Soares, P. Trzesniak, and G. A. Abraham, "Resistive‐type humidity sensors based on PVP–Co and PVP–I2 complexes," Journal of Polymer Science Part B: Polymer Physics, vol. 39, pp. 459-469, 2001.
[135] D. Santhiya, G. Nandini, S. Subramanian, K. Natarajan, and S. Malghan, "Effect of polymer molecular weight on the absorption of polyacrylic acid at the alumina-water interface," Colloids and Surfaces A: Physicochemical and Engineering Aspects, vol. 133, pp. 157-163, 1998.
[136] R. Hodge, G. H. Edward, and G. P. Simon, "Water absorption and states of water in semicrystalline poly (vinyl alcohol) films," Polymer, vol. 37, pp. 1371-1376, 1996.
[137] M. Silberberg‐Bouhnik, O. Ramon, I. Ladyzhinski, S. Mizrahi, and Y. Cohen, "Osmotic deswelling of weakly charged poly (acrylic acid) solutions and gels," Journal of Polymer Science Part B: Polymer Physics, vol. 33, pp. 2269-2279, 1995.
[138] C. W. Liew, H. Ng, A. Numan, and S. Ramesh, "Poly (Acrylic acid)–Based Hybrid Inorganic–Organic Electrolytes Membrane for Electrical Double Layer Capacitors Application," Polymers, vol. 8, p. 179, 2016.
[139] H. Park and J. R. Robinson, "Mechanisms of mucoadhesion of poly (acrylic acid) hydrogels," Pharmaceutical research, vol. 4, pp. 457-464, 1987.
[140] H. Nishide, N. Oki, and E. Tsuchida, "Complexation of poly (acrylic acid) s with uranyl ion," European Polymer Journal, vol. 18, pp. 799-802, 1982.
[141] A. Arslan, S. Kıralp, L. Toppare, and A. Bozkurt, "Novel conducting polymer electrolyte biosensor based on poly (1-vinyl imidazole) and poly (acrylic acid) networks," Langmuir, vol. 22, pp. 2912-2915, 2006.
[142] M. Genovese, J. Jiang, K. Lian, and N. Holm, "High capacitive performance of exfoliated biochar nanosheets from biomass waste corn cob," Journal of Materials Chemistry A, vol. 3, pp. 2903-2913, 2015.
[143] A. Gestos, P. G. Whitten, G. M. Spinks, and G. G. Wallace, "Crosslinking neat ultrathin films and nanofibres of pH-responsive poly (acrylic acid) by UV radiation," Soft Matter, vol. 6, pp. 1045-1052, 2010.
105
[144] Z. Adamczyk, A. Bratek, B. Jachimska, T. Jasiński, and P. Warszyński, "Structure of poly (acrylic acid) in electrolyte solutions determined from simulations and viscosity measurements," The Journal of Physical Chemistry B, vol. 110, pp. 22426-22435, 2006.
[145] M. I. Baker, S. P. Walsh, Z. Schwartz, and B. D. Boyan, "A review of polyvinyl alcohol and its uses in cartilage and orthopedic applications," Journal of Biomedical Materials Research Part B: Applied Biomaterials, vol. 100, pp. 1451-1457, 2012.
[146] M. E. Kagan and M. N. Yardney, "Interelectrode separator for rechargeable batteries," ed: Google Patents, 1953.
[147] A. Polak, S. Petty-Weeks, and A. Beuhler, "Applications of novel proton-conducting polymers to hydrogen sensing," Sensors and Actuators, vol. 9, pp. 1-7, 1986.
[148] A. Bozkurt, M. Ise, K. Kreuer, W. H. Meyer, and G. Wegner, "Proton-conducting polymer electrolytes based on phosphoric acid," Solid State Ionics, vol. 125, pp. 225-233, 1999.
[149] K. K. Lian, C. Li, R. H. Jung, and J. G. Kincs, "Electrochemical cell having symmetric inorganic electrodes," ed: Google Patents, 1996.
[150] M. Kaempgen, C. K. Chan, J. Ma, Y. Cui, and G. Gruner, "Printable thin film supercapacitors using single-walled carbon nanotubes," Nano letters, vol. 9, pp. 1872-1876, 2009.
[151] M. F. El-Kady, V. Strong, S. Dubin, and R. B. Kaner, "Laser scribing of high-performance and flexible graphene-based electrochemical capacitors," Science, vol. 335, pp. 1326-1330, 2012.
[152] H. Fei, C. Yang, H. Bao, and G. Wang, "Flexible all-solid-state supercapacitors based on graphene/carbon black nanoparticle film electrodes and cross-linked poly (vinyl alcohol)–H2SO4 porous gel electrolytes," Journal of Power Sources, vol. 266, pp. 488-495, 2014.
[153] C. W. Liew, S. Ramesh, and A. Arof, "Characterization of ionic liquid added poly (vinyl alcohol)-based proton conducting polymer electrolytes and electrochemical studies on the supercapacitors," international journal of hydrogen energy, vol. 40, pp. 852-862, 2015.
[154] J. W. Rhim, H. B. Park, C. S. Lee, J. H. Jun, D. S. Kim, and Y. M. Lee, "Crosslinked poly (vinyl alcohol) membranes containing sulfonic acid group: proton and methanol transport through membranes," Journal of Membrane Science, vol. 238, pp. 143-151, 2004.
[155] J. C. Park, T. Ito, K. O. Kim, K. W. Kim, B. S. Kim, M. S. Khil, et al., "Electrospun poly (vinyl alcohol) nanofibers: effects of degree of hydrolysis and enhanced water stability," Polymer journal, vol. 42, p. 273, 2010.
[156] J. Li, Z. Suo, and J. J. Vlassak, "Stiff, strong, and tough hydrogels with good chemical stability," Journal of Materials Chemistry B, vol. 2, pp. 6708-6713, 2014.
106
[157] S. Vicini, M. Castellano, M. C. Faria Soares Lima, P. Licinio, and G. Goulart Silva, "Polyacrylamide hydrogels for stone restoration: Effect of salt solutions on swelling/deswelling degree and dynamic correlation length," Journal of Applied Polymer Science, vol. 134, 2017.
[158] M. S. Johnson, "The effects of gel‐forming polyacrylamides on moisture storage in sandy soils," Journal of the Science of Food and Agriculture, vol. 35, pp. 1196-1200, 1984.
[159] A. Bhardwaj, I. Shainberg, D. Goldstein, D. Warrington, and G. J Levy, "Water retention and hydraulic conductivity of cross-linked polyacrylamides in sandy soils," Soil Science Society of America Journal, vol. 71, pp. 406-412, 2007.
[160] S. Sumathi, V. Sethuprakhash, and W. Basirun, "A Comparative Studies on Methanesulfonic and p-Touluene Sulfonic Acid Incorporated Polyacrylamide Gel Polymer Electrolyte for Tin-Air Battery," World Academy of Science, Engineering and Technology, International Journal of Chemical, Molecular, Nuclear, Materials and Metallurgical Engineering, vol. 7, pp. 948-953, 2013.
[161] Q. Tang, H. Cai, S. Yuan, X. Wang, and W. Yuan, "Enhanced proton conductivity from phosphoric acid-imbibed crosslinked 3D polyacrylamide frameworks for high-temperature proton exchange membranes," International Journal of Hydrogen Energy, vol. 38, pp. 1016-1026, 2013.
[162] H. J. Kim, K. Talukdar, Y. H. Kim, Y. Park, H. C. Lee, and S. J. Choi, "Study of Semi-Interpenetrating Networks in Nafion®/Polyacrylamide Proton Conducting Membranes," Journal of Nanoelectronics and Optoelectronics, vol. 10, pp. 569-573, 2015.
[163] D. Rodriguez, C. Jegat, O. Trinquet, J. Grondin, and J. Lassegues, "Proton conduction in poly (acrylamide)-acid blends," Solid State Ionics, vol. 61, pp. 195-202, 1993.
[164] W. Wieczorek, J. R. Stevens, and Z. Florjanczyk, "Proton conducting polymer gels based on a polyacrylamide matrix," Electrochimica Acta, vol. 40, pp. 2327-2330.
[165] W. Wieczorek and J. Stevens, "Proton transport in polyacrylamide based hydrogels doped with H3PO4 or H2SO4," Polymer, vol. 38, pp. 2057-2065, 1997.
[166] D. Eustace, D. Siano, and E. Drake, "Polymer compatibility and interpolymer association in the poly (acrylic acid)–polyacrylamide–water ternary system," Journal of applied polymer science, vol. 35, pp. 707-716, 1988.
[167] M. Moharram, L. Balloomal, and H. El‐Gendy, "Infrared study of the complexation of poly (acrylic acid) with poly (acrylamide)," Journal of applied polymer science, vol. 59, pp. 987-990, 1996.
[168] Y. Qiu and K. Park, "Environment-sensitive hydrogels for drug delivery," Advanced drug delivery reviews, vol. 53, pp. 321-339, 2001.
107
[169] Z. Liu and G. Rempel, "Preparation of superabsorbent polymers by crosslinking acrylic acid and acrylamide copolymers," Journal of Applied Polymer Science, vol. 64, pp. 1345-1353, 1997.
[170] T. Uma and M. Nogami, "Proton-conducting glass electrolyte," Analytical chemistry, vol. 80, pp. 506-508, 2008.
[171] A. B. Bourlinos, K. Raman, R. Herrera, Q. Zhang, L. A. Archer, and E. P. Giannelis, "A liquid derivative of 12-tungstophosphoric acid with unusually high conductivity," Journal of the American Chemical Society, vol. 126, pp. 15358-15359, 2004.
[172] M. Yamada and I. Honma, "Heteropolyacid-encapsulated self-assembled materials for anhydrous proton-conducting electrolytes," The Journal of Physical Chemistry B, vol. 110, pp. 20486-20490, 2006.
[173] H. Gao and K. Lian, "Characterizations of proton conducting polymer electrolytes for electrochemical capacitors," Electrochimica Acta, vol. 56, pp. 122-127, 2010.
[174] H. Gao, A. Virya, and K. Lian, "Monovalent silicotungstate salts as electrolytes for electrochemical supercapacitors," Electrochimica Acta, vol. 138, pp. 240-246, 2014.
[175] C. Rocchiccioli-Deltcheff, M. Fournier, R. Franck, and R. Thouvenot, "Vibrational investigations of polyoxometalates. 2. Evidence for anion-anion interactions in molybdenum (VI) and tungsten (VI) compounds related to the Keggin structure," Inorganic Chemistry, vol. 22, pp. 207-216, 1983.
[176] R. Thouvenot, M. Fournier, R. Franck, and C. Rocchiccioli-Deltcheff, "Vibrational investigations of polyoxometalates. 3. Isomerism in molybdenum (VI) and tungsten (VI) compounds related to the Keggin structure," Inorganic Chemistry, vol. 23, pp. 598-605, 1984.
[177] L. Swenson, J. C. Orozco, J. A. Kaduk, and M. I. Khan, "Electrostatic self-assembly of composite materials containing Keggin structure polyoxoanions and functionalized Anderson structure polyoxometallic cations," Inorganica Chimica Acta, vol. 444, pp. 43-50, 2016.
[178] M. Genovese, Y. W. Foong, and K. Lian, "The unique properties of aqueous polyoxometalate (POM) mixtures and their role in the design of molecular coatings for electrochemical energy storage," Electrochimica Acta, 2016.
[179] I. K. Song and M. A. Barteau, "Redox properties of Keggin-type heteropolyacid (HPA) catalysts: effect of counter-cation, heteroatom, and polyatom substitution," Journal of molecular catalysis A: Chemical, vol. 212, pp. 229-236, 2004.
[180] I. K. Song, R. B. Shnitser, J. J. Cowan, C. L. Hill, and M. A. Barteau, "Nanoscale characterization of redox and acid properties of Keggin-type heteropolyacids by scanning tunneling microscopy and tunneling spectroscopy: Effect of heteroatom substitution," Inorganic chemistry, vol. 41, pp. 1292-1298, 2002.
108
[181] U. Mioč, P. Colomban, and A. Novak, "Infrared and Raman study of some heteropolyacid hydrates," Journal of Molecular Structure, vol. 218, pp. 123-128, 1990.
[182] Q. Wu, "Synthesis and conductivity of tritungstovanadoselenic heteropoly acid," Materials Letters, vol. 50, pp. 78-81, 2001.
[183] E. M. Serwicka and C. P. Grey, "ESR and solid state MAS NMR study of the silica-supported H3+nPVnMo12−nO40 (n= O, 1, 2, 3) heteropolyacids," Colloids and surfaces, vol. 45, pp. 69-82, 1990.
[184] U. Mioč, M. Todorović, M. Davidović, P. Colomban, and I. Holclajtner-Antunović, "Heteropoly compounds—From proton conductors to biomedical agents," Solid State Ionics, vol. 176, pp. 3005-3017, 2005.
[185] A. Micek-Ilnicka, "The role of water in the catalysis on solid heteropolyacids," Journal of Molecular Catalysis A: Chemical, vol. 308, pp. 1-14, 2009.
[186] O. Nakamura, I. Ogino, and T. Kodama, "Temperature and humidity ranges of some hydrates of high-proton-conductive dodecamolybdophosphoric acid and dodecatungstophosphoric acid crystals under an atmosphere of hydrogen or either oxygen or air," Solid State Ionics, vol. 3, pp. 347-351, 1981.
[187] K. Kreuer, M. Hampele, K. Dolde, and A. Rabenau, "Proton transport in some heteropolyacidhydrates a single crystal PFG-NMR and conductivity study," Solid State Ionics, vol. 28, pp. 589-593, 1988.
[188] J. J. Altenau, M. T. Pope, R. A. Prados, and H. So, "Models for heteropoly blues. Degrees of valence trapping in vanadium (IV)-and molybdenum (V)-substituted Keggin anions," Inorganic Chemistry, vol. 14, pp. 417-421, 1975.
[189] M. Forsyth, J. Sun, D. MacFarlane, and A. Hill, "Compositional dependence of free volume in PAN/LiCF3SO3 polymer‐in‐salt electrolytes and the effect on ionic conductivity," Journal of Polymer Science Part B: Polymer Physics, vol. 38, pp. 341-350, 2000.
[190] P. Colomban, Proton Conductors: Solids, membranes and gels-materials and devices vol. 2: Cambridge University Press, 1992.
[191] Y. Li, H. Wang, Q. Wu, X. Xu, S. Lu, and Y. Xiang, "A poly (vinyl alcohol)-based composite membrane with immobilized phosphotungstic acid molecules for direct methanol fuel cells," Electrochimica Acta, vol. 224, pp. 369-377, 2017.
[192] L. Li, L. Xu, and Y. Wang, "Novel proton conducting composite membranes for direct methanol fuel cell," Materials Letters, vol. 57, pp. 1406-1410, 2003.
[193] W. Xu, C. Liu, X. Xue, Y. Su, Y. Lv, W. Xing, et al., "New proton exchange membranes based on poly (vinyl alcohol) for DMFCs," Solid State Ionics, vol. 171, pp. 121-127, 2004.
109
[194] K. Lian and Q. Tian, "Solid asymmetric electrochemical capacitors using proton-conducting polymer electrolytes," Electrochemistry Communications, vol. 12, pp. 517-519, 2010.
[195] C. Li and R. H. Reuss, "Electrochemical capacitor with solid electrolyte," ed: Google Patents, 1999.
[196] C. Li, R. H. Reuss, and M. Chason, "Electrochemical capacitor with hybrid polymer polyacid electrolyte," ed: Google Patents, 1998.
[197] V. Goffman, V. Sleptsov, N. Kovyneva, N. Gorshkov, O. Telegina, and A. Gorokhovsky, "Effect of Nanosized Potassium Polytitanate on the Properties of Proton-Conducting Composite Based on Phosphotungstic Acid and Polyvinyl Alcohol," Theoretical and Experimental Chemistry, vol. 52, pp. 318-322, 2016.
[198] H. Gao and K. Lian, "High rate all-solid electrochemical capacitors using proton conducting polymer electrolytes," Journal of Power Sources, vol. 196, pp. 8855-8857, 2011.
[199] H. Gao, Q. Tian, and K. K. Lian, "Proton conducting polymer electrolytes for electrochemical capacitors," ECS Transactions, vol. 28, pp. 77-82, 2010.
[200] H. Gao, Q. Tian, and K. Lian, "Polyvinyl alcohol-heteropoly acid polymer electrolytes and their applications in electrochemical capacitors," Solid State Ionics, vol. 181, pp. 874-876, 2010.
[201] K. Lian and C. M. Li, "Solid polymer electrochemical capacitors using heteropoly acid electrolytes," Electrochemistry Communications, vol. 11, pp. 22-24, 2009.
[202] H. Gao and K. Lian, "A H5BW12O40-polyvinyl alcohol polymer electrolyte and its application in solid supercapacitors," Journal of Materials Chemistry A, vol. 4, pp. 9585-9592, 2016.
[203] M. Forsyth, P. Meakin, and D. MacFarlane, "A 13 C NMR study of the role of plasticizers in the conduction mechanism of solid polymer electrolytes," Electrochimica acta, vol. 40, pp. 2339-2342, 1995.
[204] D. MacFarlane, J. Sun, P. Meakin, P. Fasoulopoulos, J. Hey, and M. Forsyth, "Structure-property relationships in plasticized solid polymer electrolytes," Electrochimica acta, vol. 40, pp. 2131-2136, 1995.
[205] J. Lassegues, J. Grondin, M. Hernandez, and B. Maree, "Proton conducting polymer blends and hybrid organic inorganic materials," Solid State Ionics, vol. 145, pp. 37-45, 2001.
[206] S. Majid and A. Arof, "Electrical behavior of proton-conducting chitosan-phosphoric acid-based electrolytes," Physica B: Condensed Matter, vol. 390, pp. 209-215, 2007.
110
[207] P. Donoso, W. Gorecki, C. Berthier, F. Defendini, C. Poinsignon, and M. Armand, "NMR, conductivity and neutron scattering investigation of ionic dynamics in the anhydrous polymer protonic conductor PEO(H3PO4)x," Solid State Ionics, vol. 28, pp. 969-974, 1988.
[208] P. Gupta and K. Singh, "Characterization of H3PO4 based PVA complex system," Solid State Ionics, vol. 86, pp. 319-323, 1996.
[209] J. Lassegues, B. Desbat, O. Trinquet, F. Cruege, and C. Poinsignon, "From model solid-state protonic conductors to new polymer electrolytes," Solid State Ionics, vol. 35, pp. 17-25, 1989.
[210] A. Schechter and R. F. Savinell, "Imidazole and 1-methyl imidazole in phosphoric acid doped polybenzimidazole, electrolyte for fuel cells," Solid State Ionics, vol. 147, pp. 181-187, 2002.
[211] R. Alves, F. Sentanin, R. Sabadini, A. Pawlicka, and M. M. Silva, "Influence of cerium triflate and glycerol on electrochemical performance of chitosan electrolytes for electrochromic devices," Electrochimica Acta, vol. 217, pp. 108-116, 2016.
[212] R. F. Marcondes, P. S. D'Agostini, J. Ferreira, E. M. Girotto, A. Pawlicka, and D. C. Dragunski, "Amylopectin-rich starch plasticized with glycerol for polymer electrolyte application," Solid State Ionics, vol. 181, pp. 586-591, 2010.
[213] A. Pawlicka, M. Danczuk, W. Wieczorek, and E. Zygadło-Monikowska, "Influence of plasticizer type on the properties of polymer electrolytes based on chitosan," The Journal of Physical Chemistry A, vol. 112, pp. 8888-8895, 2008.
[214] H. Gao, A. Virya, and K. Lian, "Proton conducting H5BW12O40 electrolyte for solid supercapacitors," Journal of Materials Chemistry A, vol. 3, pp. 21511-21517, 2015.
[215] M. Genovese, Y. W. Foong, and K. Lian, "Germanomolybdate (GeMo12O404−) Modified
Carbon Nanotube Composites for Electrochemical Capacitors," Electrochimica Acta, vol. 117, pp. 153-158, 1/20/ 2014.
[216] J. Biener, M. Stadermann, M. Suss, M. A. Worsley, M. M. Biener, K. A. Rose, et al., "Advanced carbon aerogels for energy applications," Energy & Environmental Science, vol. 4, pp. 656-667, 2011.
[217] P. Taberna, P. Simon, and J.-F. Fauvarque, "Electrochemical characteristics and impedance spectroscopy studies of carbon-carbon supercapacitors," Journal of The Electrochemical Society, vol. 150, pp. A292-A300, 2003.
[218] F. Wolfart, D. P. Dubal, M. Vidotti, R. Holze, and P. Gómez-Romero, "Electrochemical supercapacitive properties of polypyrrole thin films: influence of the electropolymerization methods," Journal of Solid State Electrochemistry, vol. 20, pp. 901-910, 2016.
111
[219] K. Nakajima, K. Eda, and S. Himeno, "Effect of the Central Oxoanion Size on the Voltammetric Properties of Keggin-Type [XW12O40]n−(n= 2− 6) Complexes," Inorganic chemistry, vol. 49, pp. 5212-5215, 2010.
[220] U. Lavrencic Štangar, N. Grošelj, B. Orel, and P. Colomban, "Structure of and interactions between P/SiWA keggin nanocrystals dispersed in an organically modified electrolyte membrane," Chemistry of materials, vol. 12, pp. 3745-3753, 2000.
[221] G. Zukowska, J. Stevens, and K. Jeffrey, "Anhydrous gel electrolytes doped with silicotungstic acid," Electrochimica acta, vol. 48, pp. 2157-2164, 2003.
[222] A. J. Bridgeman, "Density functional study of the vibrational frequencies of α-Keggin heteropolyanions," Chemical physics, vol. 287, pp. 55-69, 2003.
[223] G. Brown, M. Noe-Spirlet, W. Busing, and H. Levy, "Dodecatungstophosphoric acid hexahydrate, (H5O2
+)3(PW12O403−). The true structure of Keggin'spentahydrate'from
single-crystal X-ray and neutron diffraction data," Acta Crystallographica Section B: Structural Crystallography and Crystal Chemistry, vol. 33, pp. 1038-1046, 1977.
[224] H. Gao and K. Lian, "Advanced proton conducting membrane for ultra-high rate solid flexible electrochemical capacitors," Journal of Materials Chemistry, vol. 22, pp. 21272-21278, 2012.
[225] M. K. Gupta and R. Bansil, "Laser Raman spectroscopy of polyacrylamide," Journal of Polymer Science: Polymer Physics Edition, vol. 19, pp. 353-360, 1981.
[226] X. Lu and Y. Mi, "Characterization of the interfacial interaction between polyacrylamide and silicon substrate by Fourier transform infrared spectroscopy," Macromolecules, vol. 38, pp. 839-843, 2005.
[227] A. Oyane, K. Nakanishi, H. M. Kim, F. Miyaji, T. Kokubo, N. Soga, et al., "Sol–gel modification of silicone to induce apatite-forming ability," Biomaterials, vol. 20, pp. 79-84, 1999.
[228] N. Murthy and H. Minor, "General procedure for evaluating amorphous scattering and crystallinity from X-ray diffraction scans of semicrystalline polymers," Polymer, vol. 31, pp. 996-1002, 1990.
[229] N. Murthy, H. Minor, C. Bednarczyk, and S. Krimm, "Structure of the amorphous phase in oriented polymers," Macromolecules, vol. 26, pp. 1712-1721, 1993.
[230] N. Murthy, S. Correale, and H. Minor, "Structure of the amorphous phase in crystallizable polymers: poly (ethylene terephthalate)," Macromolecules, vol. 24, pp. 1185-1189, 1991.
[231] Y. Pei, L. Zhao, G. Du, N. Li, K. Xu, and H. Yang, "Investigation of the degradation and stability of acrylamide-based polymers in acid solution: Functional monomer modified polyacrylamide," Petroleum, vol. 2, pp. 399-407, 2016.
112
[232] C. Murli and Y. Song, "Pressure-induced polymerization of acrylic acid: a Raman spectroscopic study," The Journal of Physical Chemistry B, vol. 114, pp. 9744-9750, 2010.
[233] D. E. Owens, Y. Jian, J. E. Fang, B. V. Slaughter, Y. H. Chen, and N. A. Peppas, "Thermally responsive swelling properties of polyacrylamide/poly (acrylic acid) interpenetrating polymer network nanoparticles," Macromolecules, vol. 40, pp. 7306-7310, 2007.
[234] T. Ito, K. Inumaru, and M. Misono, "Structure of porous aggregates of the ammonium salt of dodecatungstophosphoric acid,(NH4)3PW12O40: unidirectionally oriented self-assembly of nanocrystallites," The Journal of Physical Chemistry B, vol. 101, pp. 9958-9963, 1997.
[235] T. Ito, K. Inumaru, and M. Misono, "Epitaxially self-assembled aggregates of polyoxotungstate nanocrystallites, (NH4)3PW12O40: Synthesis by homogeneous precipitation using decomposition of urea," Chemistry of materials, vol. 13, pp. 824-831, 2001.
[236] J. S. Santos, J. A. Dias, S. C. Dias, F. A. Garcia, J. L. Macedo, F. S. Sousa, et al., "Mixed salts of cesium and ammonium derivatives of 12-tungstophosphoric acid: Synthesis and structural characterization," Applied Catalysis A: General, vol. 394, pp. 138-148, 2011.
[237] T. Rajkumar and G. R. Rao, "Synthesis and characterization of hybrid molecular material prepared by ionic liquid and silicotungstic acid," Materials Chemistry and Physics, vol. 112, pp. 853-857, 2008.
[238] K. Checkiewicz, G. Żukowska, and W. Wieczorek, "Synthesis and characterization of the proton-conducting gels based on PVdF and PMMA matrixes doped with heteropolyacids," Chemistry of materials, vol. 13, pp. 379-384, 2001.
[239] L. Adamczyk and K. Miecznikowski, "Solid-state electrochemical behavior of Keggin-type borotungstic acid single crystal," Journal of Solid State Electrochemistry, vol. 17, pp. 1167-1173, 2013.
[240] Z. Sun, X. Duan, J. Zhao, X. Wang, and Z. Jiang, "Homogeneous borotungstic acid and heterogeneous micellar borotungstic acid catalysts for biodiesel production by esterification of free fatty acid," Biomass and Bioenergy, vol. 76, pp. 31-42, 2015.
[241] J. Wang, J. Li, and J. Niu, "Synthesis, crystal structure and characterization of a 2-D network organic-inorganic hybrid polymer with [α-BW12O40]5− as building blocks," Science in China Series B: Chemistry, vol. 49, pp. 437-444, 2006.
[242] A. Martinelli, A. Matic, P. Jacobsson, L. Börjesson, M. A. Navarra, D. Munaò, et al., "A study on the state of PWA in PVDF-based proton conducting membranes by Raman Spectroscopy (Accepted-In Press)," Solid State Ionics, 2006.
[243] W. W. Rudolph, "Raman-and infrared-spectroscopic investigations of dilute aqueous phosphoric acid solutions," Dalton Transactions, vol. 39, pp. 9642-9653, 2010.
113
[244] J. M. Bregeault, M. Vennat, S. Laurent, J. Y. Piquemal, Y. Mahha, E. Briot, et al., "From polyoxometalates to polyoxoperoxometalates and back again; potential applications," Journal of Molecular Catalysis. A, Chemical, vol. 250, pp. 177-189, 2006.
[245] J. Dong, Y. Ozaki, and K. Nakashima, "Infrared, Raman, and near-infrared spectroscopic evidence for the coexistence of various hydrogen-bond forms in poly (acrylic acid)," Macromolecules, vol. 30, pp. 1111-1117, 1997.
[246] N. Tanaka, H. Kitano, and N. Ise, "Raman spectroscopic study of hydrogen bonding in aqueous carboxylic acid solutions. 3. Polyacrylic acid," Macromolecules, vol. 24, pp. 3017-3019, 1991.
[247] E. Mendelovici, R. L. Frost, and T. Kloprogge, "Cryogenic Raman spectroscopy of glycerol," Journal of Raman Spectroscopy, vol. 31, pp. 1121-1126, 2000.
[248] A. Mudalige and J. E. Pemberton, "Raman spectroscopy of glycerol/D2O solutions," Vibrational Spectroscopy, vol. 45, pp. 27-35, 2007.
114
Appendix A – Raman and FTIR Peak Assignments
This section presents the peak assignments for the Raman spectra for each of the samples
discussed in this thesis. Table 9 and Table 10 were the Raman and FTIR peak assignments for
SiWA and BWA. Table 11 and Table 12 were the Raman and FTIR peak assignments for PAM.
Table 13, Table 14, and Table 15 were the Raman peak assignments for BWA-PAM binary