High energy and capacity cathode material for li ion battries

VISVESVARAYA TECHNOLOGICAL UNIVERSITY

centre for post graduate studies, Bangalore

seminar

on

High Capacity and High Energy Density Cathode Materials for Lithium Ion Battery

ByNatrajUSN: 1VW12INT12

Under the Guidance ofDr. Dinesh RSpecial officer, VTU CPGSB

INDEX

Introduction to Battery – Timeline

Lithium ion battery

Cathode materials

Advantages and Disadvantages of LI-Ion

Batteries

Advances in cathode materials

Promising cathode materials

Methodologies

References

Battery

A battery is a transducer that converts chemical

energy into electrical energy and vice versa.

It contains

An anode - source

A cathode - sink

An electrolyte - the separation of ionic

transport and electronic transport

Types: Primary and secondary

Timeline for the major events in the history of batteries

Introduction to Li-Ion Battery

The name of “lithium ion battery” was given by T. Nagaura and K. Tozawa

The concept of “lithium ion battery” was firstly introduced by Asahi Kasei Co. Ltd

Lithium ion batteries were first proposed by M. S. Whittingham in the 1970’s. Whittingham used TiS2 as the cathode and Lithium metal as the anode.

The first commercial lithium-ion battery was released by Sony in 1991

Why Li-Ion Battery?

Li is lightest metal

one of the highest standard reduction potentials (-3.0 V)

Theoretical specific capacity of 3860 Ah/kg in comparison with 820 Ah/kg for Zn and 260 Ah/kg for Pb

performance is related not only capacity but also to how fast current can be drawn from it: specific energy (Wh/Kg), energy density (Wh/cm3) and power density (W/Kg)

Schematic representation of a Lithium-ion cell

Advantages of Lithium-ion batteries

POWER – High energy density means greater power in a smaller package.

◦ 160% greater than NiMH

◦ 220% greater than NiCd

HIGHER VOLTAGE – a strong current allows it to power complex mechanical devices.

LONG SHELF-LIFE – only 5% discharge loss per month.

10% for NiMH, 20% for NiCd

Disadvantages of Lithium-ion batteries

EXPENSIVE

DELICATE

REGULATIONS

Cathode materials

A cathode is the electrode of an electrochemical cell at which reduction occurs

Common cathode materials of Lithium-ion batteries are the transition metal oxide based compounds such as LiCoO2, LiMn2O4, LiNiO2, LiFePO4

characteristics of cathode materials

A high discharge voltage

A high energy capacity

A long cycle life

A high power density

Light weight

Low self-discharge

Parameters effecting Cathode behavior

Method of preparation

Particle size

Morphology

Temperature

CATHODE MATERIALS

Material Structure

Potential vs. Li/Li+, average v

Specific capacity, mAh/g

Specific energy, Wh/kg

LiCoO2 Layered 3.9 140 546

LiNi0.8Co0.15Al0.05O2

(NCA)

Layered 3.8 180-200 680-760

LiNi1/3Co1/3Mn1/3O2

(NMC)

Layered 3.8 160-170 610-650

LiMn2O4 Spinel 4.1 100-120 410-492

LiFePO4 olivine 3.45 150-170 518-587

Ways to Improve Cathode Performance

• Increasing Energy Density

• Thin nano-plate materials

• 30 nm LiFePO4 nano-plates performed better than thick

material

• Surface Coating of cathodes with either ionically or

electronically conductive material

• AlF3 coating on oxide materials is shown to improve

performance

Problems in the usage of Cathode materials

Raw material cost

Environmental impact of large-scale cells and mass

production

Production cost of solid-state synthesis using high and long

heating process

Heat generation from the cathode in a fully charged state

Sensitivity of safety for charge cutoff voltages

Low practical capacity of the cathode being half that of a

carbonaceous anode

Methodologies

There are several methods to synthesize the cathode materials of average

particle size and good crystallinity.

Hydrothermal process

Solvothermal process

Supercritical fluid process

Spray pyrolysis process

Conclusions and what does the future hold

In present day common Lithium transition compounds such as

LiCoO2, LiNiO2, LiMn2O4 and LiFePO4 are used as cathode material

in battery cell production, and they have shown a good performance

during charge and discharge cycling

For the future there are still a number of actions of interest to further

develop the performance of derived LiFePO4/C cathode material

We expect upcoming researches on this new framework will lead to

better cathode materials for lithium-ion batteries

References•Directed growth of nanoarchitectured LiFePO4 electrode by solvothermal synthesis and their

cathode properties

Authors: Dinesh Rangappa, Koji Sone, Tetsuichi Kudo, Itaru Honma

•Synthesis of LiMn2O4 nanoparticles made by flame spray pyrolysis

Authors: T. J. Patey,ab R. Bu¨ chel,c M. Nakayamab and P. Nova´k*a

•Monodisperse Porous LiFePO4 Microspheres for a High Power Li-Ion Battery Cathode by

Solvothermal process

Authors: Chunwen Sun, Shreyas Rajasekhara, John B. Goodenough,* and Feng Zhou

•Flame spray-pyrolyzed vanadium oxide nanoparticles for lithium battery cathodes

Authors: See-How Ng, Timothy J. Patey et.al

•Rapid one-pot synthesis of LiMPO4 (M = Fe, Mn) colloidal nanocrystals by supercritical

ethanol process

Authors: Dinesh Rangappa,* Koji Sone, Masaki Ichihara, Tetsuichi Kudob and Itaru Honma*

•Recent developments in cathode materials for lithium ion batteries

Author: Jeffrey W. Fergus ……. and

many more