ENGINEERED FIBERS TECHNOLOGY Porous Graphite Materials Development for Specific Electrochemical Applications Presented By: Robert E. Evans Hannover Messe April 13-17, 2015
ENGINEEREDFIBERS
TECHNOLOGY
Porous Graphite Materials Development for Specific
Electrochemical Applications
Presented By:
Robert E. EvansHannover MesseApril 13-17, 2015
Engineered Fibers TechnologyEstablished 1998
Engineered Fibers TechnologyEstablished 1998
Technical Expertise- Founding Members Each
With Over 30 Years Experience - Fibers / Composites / Paper
Providing High Technology Fibers /Materials / Services
Located in Shelton, CT(1950 Sq. Meters)
- Fiber Processing- Materials Development Lab- Spectracarb Development
Technical Expertise- Founding Members Each
With Over 30 Years Experience - Fibers / Composites / Paper
Providing High Technology Fibers /Materials / Services
Located in Shelton, CT(1950 Sq. Meters)
- Fiber Processing- Materials Development Lab- Spectracarb Development
Spectracarb GDL Background
From 1991-2005, Spectracorp. Ltd was
Leading producer of GDL products for commercial application- SpectracarbTM GDL
Leader in development of new GDL materialsDOE ContractsAutomotive / Industrial Sponsorship
Spectracarb GDL Background
Since 2005 EFT has grown Spectracarb Porous Graphite Materials through: Engineered Materials Research Wet-Laid Paper Development Specialty Short-Cut Fiber Investigations
Partnership with Caplinq Europe BV Since 2013
Technology Focus is Customer Driven / Customer Responsive GDL Development
Wet-Laid Resin Bonded Paper / Panels
Nonwoven Needle Punched Felts / Woven Fabrics
Production of Porous GDL Materials
Wet-Laid GDL Paper General Processing Schemes
PAN Filament
Carbon Filament
Carbon Fiber Slurry
Bonded Graphite Fiber Paper / Panel
Other Components
Resin Impregnation
Specific Porous Graphite Paper /
Panel
Wide Range of Carbon Fibers Available from producers Stabilization /
Graphitization900- 3000oC
Stabilization, carbonization
Precision Cutting
Molding /Resin CuringPaper Formation
Optional Wet-proofing, MPL
coating, sintering
Advantages of Papermaking Approach for Specialized GDL Products
Versatility - Wide Range of Fibers / Particle Modifiers/Binders Can be Included in Papermaking
Thickness / Density /Porosity Control
High Density /Thick Panels with High Compressive Compliance / Low Flow Channel Intrusion
Preparation on Laboratory / Pilot / Production Scale
Small Production Runs Possible
EFT / Spectracarb GDL Macroporous Graphite Materials EFT / Spectracarb GDL Macroporous Graphite Materials
Very High Conductivity Porous Graphite Papers / Panels
High Strength and Durability
Good Air Permeability
Moisture Transport / Water Management
Lab-Scale Prototype Development to Commercial Scale Manufacturing
Produced in US / Caplinq European Agent
Very High Conductivity Porous Graphite Papers / Panels
High Strength and Durability
Good Air Permeability
Moisture Transport / Water Management
Lab-Scale Prototype Development to Commercial Scale Manufacturing
Produced in US / Caplinq European Agent
Spectracarb GDL Technology FocusProvide lower cost products that are
interchangeable with other existing standard grades
Development / Commercial Production of GDL products meeting specific customer requirements / electrochemical applications
Creation of “Next Generation” GDL productsJoint Development / Engineering ProgramsIndependent / Contract Research
China City Bus Program –Fuel Cell Technology
Shanghai Shen-Li Fuel Cell Production
2008 Olympics /2010 World Expo
Spectracarb 2050A-0850 GDL –Good Performance with Lowest Cost
Several Thousand Sheets, 0.2 mm Supplied
Spectracarb 2050A-0850 Properties
Measurement Units Spectracarb2050A-0850
Thickness mm 0.20
Basis Weight g/m2 88
Geometric Density g/cm3 0.44
Mean Pore Size micron 27
Air Permeability, through-plane
cfm/ft2 35
Electrical Resistivitythrough-planein-plane
mW·cm2
mW·cm
185.4
Thermal Conductivitythrough-plane (@
25°C)through-plane (@
100°C)in-plane (@ 25°C)in-plane (@ 100°C)
W/m·K3.43.6
20.724.2
Tensile StrengthMDXMD
MPa 4.22.6
Flexural Strength MPa 37
Flexural Stiffness GPa 9.5
Compressive Strength MPa 2.1
Spectracarb GDL Technology FocusProvide lower cost products that are
interchangeable with other existing standard grades
Development / Commercial Production of GDL products meeting specific customer requirements / electrochemical applications
Creation of “Next Generation” GDL productsJoint Development / Engineering ProgramsIndependent / Contract Research
Porous Graphite Papers/Panels Used in Range of Devices
PEM / PA Fuel CellsRedox Flow Batteries PEM ElectrolyzersHumidifiers Electrochemical Reactors
It Should Not Be Expected That One Material - Or Family of Materials - Will be Optimum for All Applications
Lower Cost (Second Generation) GDL Investigations for Automotive Applications-GM Sponsored
Graphs from MS&T 2009/2011 Conferences –Nicotera et al
Engineered GDL for Improved Water Management
Anode GDL (Higher Diffusion Resistance) Cathode GDL (Standard Construction)
US Patent 8518596 B1 “Low cost fuel cell diffusion layer configured for optimized anode water management” – GM 2013
Redox Flow Batteries
Redox flow batteries (RFBs) are “flow‐through” electrochemical reactors, analogous in many respects to fuel cells Suitable for large scale, stationary energy storage applications (grid storage) Typically aqueous‐based systems: the all vanadium RFB is currently the state‐of‐the‐art (Ecell ~ 1.2‐1.6 V) RFBs feature long cycle life (> 10,000 cycles), and high cell efficiencies RFBs have low energy densities compared to other secondary battery systems (~ 15‐30 Wh/L) Many demonstration units exist world wide; kWh‐MWh capabilities Key feature of RFBs: power and energy density can be mutually exclusive (i.e. decoupled), unlike other
battery technologies; use larger tanks for higher kWh, and increase the size or number of cells for higher kW
Carbon Electrode Development
Commercial and custom‐made carbon papers and felts are being examined for improved electrocatalyticactivity
Various thermal, chemical, and electrochemical treatments can be used to modify the electrocatalytic activity of carbon electrodes
Unmodified Spectracarb 1550 carbon paper shows improved electrochemical reversibility and catalytic activity when compared to common commercial grade carbon paper used in various RFB systems
RFB performance metrics:CE = td/tc x 100%VE = Vd/Vc x 100%EE = CE x VE
Vanadium Redox BatteryPorous Electrodes
Literature Reference Shows Porous Carbon Papers Have Better Performance than Felts (Q.H. Liu – J. of Electrochemical Society -2012)
Spectracarb 1550 Shows Better Performance than Other Commercial Paper (UKy)
Spectracarb 1550 Being Used as Baseline For Continuing Development / Customer Specific Targets –EFT Program
Reference Also Shows Effect of Thickness (Number of Stacked Sheets of Paper): Suggests Thicker Panels May Increase Performance
Spectracarb 2050A-1550 Properties
Measurement Units Spectracarb2050A‐1550
Sheet size mm 400 x 400
Thickness mm 0.350
Basis Weight g/m2 175
Geometric Density g/cm3 0.50
Air Permeability, through‐plane cfm/ft2 35
Electrical Resistivitythrough‐plane (@ 200 kPa)in‐plane
mW∙cm2
mW∙cm155.4
Thermal Conductivitythrough‐plane (@ 25°C)through‐plane (@ 100°C)in‐plane (@ 25°C)in‐plane (@ 100°C)
W/m∙K3.43.620.724.2
Flexural Strength MPa 40
Porosity % 78
PEM Electrolyzer Cathode Current Collector
Laboratory Electrolyzer with Spectracarb Cathode Current Collectors- Curiosity SINTEF
Spectracarb Panels for Electrolyzer Cathode Current Collectors
Lower Cost Alternative to Titanium Mesh / Sintered Ti
Thicker Plates (Up to 5mm) Higher Density (up to one
g/cm3) Higher Bending Stiffness vs
Stacking of Thin Papers Function as Elastic Springs
in Compression (30%) Machinability Hybrid Constructions
Possible
Properties- Spectracarb Electrolyzer Panel (12580)- Elastic Springs
0,0
5,0
10,0
15,0
20,0
25,0
0 200 400 600 800 1000
Stra
in, %
Stress. PSI
Percent Strain 1Percent Strain 2
Thin GDL with same requirements as Fuel Cell Except Conductivity / Graphitization Not Necessary
Paper Based on Glass / Ceramic Fiber- High Purity Resin Binder
US Patent 8974977 “Wetside Paper for Fuel Cell Humidifier” GM 2015
Other Specific Designs for Electrochemical ApplicationsHumidifiers for Fuel Cells Electrolyzers for
Chemical Electrolysis Thicker Electrode Panels
Similar to Water Electrolysis with High Flow (HF) –Larger Average Pore Size / Higher Porosity / Low Pressure Drop
US Patent 7341654 “Mediated Hydrohalic Electrolyzers” (2008)
Spectracarb Technology FocusProvide lower cost products that are
interchangeable with other existing standard grades
Development / Commercial Production of GDL products meeting specific customer requirements / electrochemical applications
Creation of “Next Generation” GDL products Joint Development / Engineering Programs Independent / Contract Research