PNNL

Abstract

Occasional fire accidents and continuous battery safety concerns require advanced lithium ion batteries (LIBs) with high safety as well as great battery performances. The electrolyte plays a critical role in electrochemical and safety properties. Organic phosphate solvents next to the state-of-the-art organic carbonates could formulate nonflammable electrolytes and intrinsically eliminate fire hazards, but their poor compatibility with the graphite anodes remains an obstacle for practical applications. This work reports a promising approach by formulating localized high concentration electrolytes based on a phosphate solvent, ethylene carbonate and a partially fluorinated ether. This electrolyte readily generates robust solid electrolyte interphase on graphite anode and cathode electrolyte interphase on LiNi0.8Mn0.1Co0.1O2 (NMC811) cathode. As a result, this electrolyte shows good compatibility with high voltage cathode and graphite anode, and enables long-term cycling stability in graphite||NMC811 cells. This work sheds a new light in development of nonflammable electrolytes for high energy-density LIBs.