Graphene and Graphene-like Composites for anode materials in Li-ion battery Applications

1. Graphene and Graphene-like Composites for anode materials in Li-ion battery Applications Proposal Presentation PHYS-570X Presented by Suprem R. Das Department of Physcs, and Birck Nanotechnology CenterPurdue UniversityWest Lafayette, IN

2. Graphene and Graphene-like Composites for anode materials in Li-ion battery Applications Seed research proposal submitted by Suprem Ranjan Das† † The Birck Nanotechnology Center and Department of Physics, Purdue University, West Lafayette, IN Single layer graphene and few layer graphene, are recently shown to have numerous scientific and technological break-throughs having novel nanodevice applications, the most important ones being potential candidate for electronics and sensor applications. However, in order to drive these complex and tiny devices and circuits one needs the compatible power supply systems that must fit into the same circuits. Due to its very high electronic conductivity, this material could be thought of as fabricating the anode electrode in the Li-ion battery. In this proposal, we discuss the various approaches to make different types of graphene powders (both elemental and composite) and later use these materials to fabricate the anode for Li-ion battery. Prior to using it inside an electrochemical cell, various structural techniques such as IR spectroscopy, X-ray photoelectron spectroscopy and Raman spectroscopy could be used to identify the correct phase of the material. A prototype device using LiMn1.5Ni0.5O4 cathode and both liquid electrolyte (EC+DMC+LiPF6) and poly ethylene oxide (PEO) solid electrolyte is discussed .

3. Trends in battery technologies Li-ion batteries are the key source of power supply for wide applications High energy density, design flexibility, and safest in use However, technological advancement is not as aggressive as semiconductor industry because of the complexity in the device Ref: Tarascon et al., Nature 414, 359, 2001

4. Charging and Discharging a Li-Ion battery • Current Li-Ion batteries use both cathode and anode as intercalated compounds • High energy density nature of a cell is a function of cell potential (V) and capacity (Ah/kg), both of which related to material chemistry <= DFT calculations Ref1: Tarascon et al., Electrochimica Acta 38, 1221, 1993 Ref2: Kganyago et al., Phys. Rev. B 68, 205111, 2003

5. Materials of Choice However, current carbon/graphite anodes show high surface area Li-plating when fast recharged Ref: Tarascon et al., Nature 414, 359, 2001

6. Motivation for the graphene-based anode • The reactivity of graphene sheet with Li-ion will be different along the plane and also along the edges (zig-zag and armchair) • In graphene based anodes, the Li-ions will be adsorbed on the two sides of the sheet and along the edges, there by increasing the capacity of the anode • Since the graphene powders are truly disordered, so the sheets are randomly oriented making it isotropic in all directions. Thus the storage of the Li-ion will be isotropic, again enhancing the capacity of the anode. • The disordered nature of the graphene based anode will overcome any kinds of ‘pulverization’ effects that is faced by recent high density intermatallic anodes, thereby expected to show improved rate capabilities • Reactivity of Li-ion towards graphene oxides or graphene-metal composite sheets may be higher than towards pure graphene, if so, it can produce even more high capacity and high rate capable Li-ion batteries

7. My Proposal: • To produce high quality graphene-anodes (both pure and composites with metals, e.g. Sn) • Use recently reported high energy LiMn1.5Ni0.5O4 spinel cathodes and layered LiMn0.5Ni0.5O2 cathodes • Fabricate prototype cells using both liquid electrolyte (EC+DMC with LiPF6 (1:1)) and PEO based solid electrolyte • 4. Study the charge-discharge behavior of the Li-ion in these cells

8. High quality graphene and graphene composite powders Exfoliation-reintercalation-expansion of graphite Reducing GO using hydrazine Dai et al, Stanford H.Dai et al., Nature Nanotechnology 3, 538, 2008 V. C. Tung et al., Nature Nanotechnology 4, 25, 2009 Electrochemical modification of graphene to synthesize Graphene-metal (Sn) composite Solvothermal synthesis and sonification M. Choucair et al., Nature Nanotechnology 4, 30, 2009 R.S. Sundaram et al., Adv. Mater. 20, 3050, 2008

9. Characterization of graphene-based materials H.Dai et al., Nature Nanotechnology 3, 538, 2008 A.C.Ferrari et al., PRL 97,187401, 2006

10. Anode fabrication

11. Cell fabrication Coin cell design Thin film Lithium battery schematic HS Test Cell HS-3E Test Cell Hand-operated crimping tool for coin cells http://www.hohsen.co.jp/ (1) J. R. Dahn et al, Electrochimica Acta 38, 1179, 1993; (2) N. J. Dudney et al, Current Opinion in Solid State and Materials Science 4, 479, 1999

12. Other instumentations • Battery tester with software and PC • Glove box with inert atmosphere facility • Vacuum oven • Mixer

13. Cathode material to be used for cell fabrication

14. Polymer electrolyte to be used

15. Expected results • Higher specific capacity for Li-ion batteries using graphene based anodes • Higher rate capabilities • High capacity retention after repeated cycling (over hundred cycles) • Safe in using in wide variety of applications

16. CONCLUSIONS • Though Carbon is the material of choice for anodes in Li-ion batteries for almost last two decades, still it has many problems • Graphene and graphene-based metal composites may overcome these obstacles • Graphene based anodes, being entirely disordered in nature and isotropic, is expected to produce high energy anodes • Due to zigzag and armchair configurations and exposures of both sides of graphene sheets to Li-ion environment, its adsorption of the same can be lot higher than the usual carbon or graphitic anodes Acknowledgements: I Acknowledge Prof Y. P. Chen and all the colleagues participating in ‘Carbon Nanophysics’ course