009

Title:

Modeling the interfacial chemistry of graphene-based composite electrode materials for Lithium Ion Battery

Discipline: Mechanical Engineering

Presenter:

Vidushi Sharma

Abstract:

High volumatic expansions, large compressive stresses and subsequent interfacial debonding are largely associated with high energy density materials such as Silicon (Si). Incorporation of additional materials such as Graphene provides Si anode a porous skeleton, allowing Si to expand/contract easily with low mechanical stresses. Graphene significantly lowers the stresses in expanding Si, thus increasing its cycle life. In this study, specific interfacial attributes which directly or indirectly contribute towards the strain accommodation in expanding electrodes have been analyzed, with aim to create a model that will help in understanding and predicting the performance of graphene provided-interface in Lithium ion batteries. For this purpose, First Principle calculations are carried out using VASP to examine interfacial chemistry of Si-Graphene system. Produced results are then further compared with additional electrode model: Tin(Sn). Sn is another high energy density material which holds promise as anode for ion batteries beyond LIB. Sn undergo strenuous phase changes during battery performance. Change in interface characteristics post phase change of electrode have also been emphasized. It was understood that interfacial cohesive energy is not merely dependent upon the atomic attributes and type of bonding with Graphene surface as mostly highlighted, but also on unaccounted for lattice mismatch between crystalline electrode and Graphene. With changing phases and deviation in lattice constants, interface adhesion changes even though bonding between electrode and Graphene remains unchanged.

Author(s):

Vidushi Sharma, Kamalika Ghatak, Dibakar Datta

Funding Acknowledgements:

Financial support from NJIT and NSF (Award 1911900 & 1911905). Computational support from ARCS, Kong and Extreme Science and Engineering Discovery Environment (XSEDE Start Up Allocation - DMR170065 & Research Allocation - DMR180013).