Inhibition of transition-metal dissolution with advanced electrolytes in batteries with silicon-graphite anodes and high-nickel cathodes

Abstract

Transition-metal (TM) ion dissolution from high-nickel cathodes and the subsequent deposition on Silicon-based anodes impose significant detrimental influence on the cell stability, hindering the application of high-energy-density lithium-ion batteries. Here, we demonstrate an effective approach to inhibit the dissolution of TM ions by using medium concentrated lithium bis(fluorosulfonyl)imide (LiFSI)-based electrolytes with an optimized fluoroethylene carbonate content. The advanced LiFSI-based electrolyte not only stabilizes the surface lattice structure of high-Ni cathodes but also effectively suppress the TM ion dissolution, which benefit from the formation of a LiF-rich solid-electrolyte interphase (SEI) layer on the LiNi0.90Mn0.05Co0.05O2 cathode surface. A robust and protective SEI layer on the SiOx/Gr anode surface is also realized with the newly developed electrolyte, which effectively alleviates anode deterioration caused by the deposited TM ions. The SiOx/Gr||LiNi0.90Mn0.05Co0.05O2 cells with such an advanced electrolyte exhibit remarkably improved cycling stability compared to those with conventional LiPF6-based electrolyte. This study provides insights towards the development of next-generation high-energy-density batteries with high-Ni cathodes and Si-based anodes.