Understanding interfacial chemistry and stability for performance improvement and fade of high-energy Li-ion battery of LiNi0.5Co0.2Mn0.3O2//silicon-graphite

Understanding the chemical processes that occur at the electrode/electrolyte interface in a battery is crucial, as the interactions between anode/cathode and electrolyte and between cathode and anode of a full-cell determine the final battery performance. We have investigated the correlation among cycling performance, interfacial reaction behavior and the solid electrolyte interphase (SEI) stability of a LiNi 0.5 Co 0.2 Mn 0.3 O 2 //Si-graphite full-cell under an aggressive test condition between 3.0 and 4.55 V using fluoroethylene carbonate (FEC)-based electrolyte, and blended additives of methyl (2,2,2-trifluoroethyl)carbonate (FEMC) and vinylene carbonate (VC). Through the formation of a stable SEI at both high-voltage cathode and anode, metal dissolution from the cathode is inhibited and full-cell achieves enhanced cycling performance. Interfacially stabilized full-cell delivers a high energy of 622 Wh per kg of active material and improved capacity retention, whereas the cell in conventional electrolyte shows a rapid performance fade.