Solvophilicity effect on the generation and evolution of solid electrolyte interface at Bi anode with excellent fast-charging performance

Abstract

The performance of electrode is extremely correlated with the solvation sheath, however, it is not clear how the solvophilicity of electrode with the solvated sheaths has a key effect on the electrochemical behavior. Herein, Bi anode is selected to reveal the solvophilicity effect on the performances of lithium ion batteries (LIBs) in two different electrolyte environments. The function of solvophilicity is primarily embodied in two aspects: one is the preferential reduction of anion-rich solvation sheath and thus rapid formation of rigid solid electrolyte interface (SEI) via the strong adsorption between Bi and solvation sheath, the other is the mild interfacial evolution from rigid SEI to rigid-soft coupling SEI via the reactivity of solvation sheath. Attributed to these superiorities, an excellent cycling performance of Bi anode can be obtained, i.e., a high volumetric capacity of 2476 mA h cm−3 at 1.3 C after 6100 cycles for 13 months and 1597 mA h cm−3 at 10 C after 6000 cycles. Besides, four kinds of Bi-based full cells are demonstrated. Notably, the Bi//NCM811 full cell delivers 97% capacity retention at 50 mA g−1 after 200 cycles. This work provides a new insight on understanding the electrochemical behavior and improving the performance from the perspective of solvophilicity.