Al–Li alloys as bifunctional sacrificial lithium sources for prelithiation of high-energy-density Li-ion batteries

Abstract

The low initial Coulombic efficiency of anodes such as Si@C can seriously affect the capacity of high-energy-density Li-ion batteries (LIBs). Supplement the initial irreversible lithium loss in the anode through prelithiation technology is the only way to realize the next generation of LIBs. In this work, we report the study of Al–Li alloy (ALA) as a prelithiation additive for LIBs cathodes. As a bifunctional sacrificial lithium source, ALA can not only provide an additional capacity of 1068 mAhg−1 to supplement the initial active lithium consumption, but also form aluminum and aluminum oxide to stabilize the cathode interface after the delithiation to improve the battery cycling stability. Therefore, the initial charge capacity of LiCoO2 (LCO) and LiNi0.6Co0.2Mn0.2O2 (NCM622) electrodes can be increased to 12.5%–18.5% by adding 2%–4% ALA. In addition, the energy density of the NCM811/Si@C pouch cell prelithiated by ALA can reach 541 Wh kg−1, which means that the cathode can maximize the capacity (from 189 mAh g−1 to 205 mAh g−1). In conclusion, this work develops a more inexpensive and efficient cathode prelithiation additive for next-generation LIBs.