Diffusion Mechanisms in the Solid Electrolyte Interphase in Li-Ion Batteries from First Principle Calculation

Tuesday, May 13, 2014: 10:40
Bonnet Creek Ballroom IV, Lobby Level (Hilton Orlando Bonnet Creek)
Z. Liu, H. W. Zhang (The Pennsylvania State University), Y. Qi (Michigan State University), S. J. Harris (Lawrence Berkeley Lab), P. Lu (General Motors R&D Center), and L. Q. Chen (The Pennsylvania State University)
The understanding of the mechanisms of Li-ion transport and electron leakage through the solid electrolyte interphase (SEI) layer is crucial to enhance the performance of rechargeable Li-ion batteries. Our study was based on a slab model of Li metal covered by Li2CO3 with contact with ethylene carbonate (EC) electrolyte. Pure Li metal is an ideal negative electrode for its high capacity and low voltage level. The layer of crystalline Li2CO3 was used to mimic the SEI layer, since our recent recognition by TEM that Li2CO3 was the component responsible for stabilizing the SEI. The barriers for Li and electron transport under applied voltage will be computed within the framework of DFT and constrained-DFT to understand the mechanism in electrochemical systems. Ab inito molecular dynamics (AIMD) simulations will be performed to explicitly track Li+ diffusion pathways. Energy profiles as a function of the electric field during this reduction reaction will be  determined to understand the effects of electric field  on the diffusion barrier.