Pre-lithiation synergized with magnesiothermic reduction to enhance the performance of SiO anode for advanced lithium-ion batteries

Abstract

Due to its high theoretical specific capacity, micron-sized silicon monoxide (SiO) is regarded as one of the most competitive anode materials for lithium-ion batteries with high specific energy density. However, originating from the low initial Coulombic efficiency (ICE) and large volume expansion, its large-scale application is seriously hindered. Herein, an easy-to-implement solid-state pre-lithiation method synergized with the magnesiothermic reduction process was performed to enhance the ICE of SiO and a common bimetallic hydride was used as a prelithiation reagent. Moreover, the effects of different pre-lithiation reagent amounts on the physical and electrochemical properties of SiO_x are investigated. Notably, the SiO_x-LA@C composite anchored by in-situ generated LiAl(SiO₃)₂ shows a more stable microstructure and excellent electrochemical properties, which delivers an ultrahigh ICE of 89.4 % and an excellent initial capacity of 1864.4 mAh g^-1. Furthermore, the full cells were successfully assembled by using the prepared anodes, which exhibit relatively stable cycle performance over 150 cycles. This work suggests a safe and feasible route to enhance the ICE of SiO_x for the applicable SiO-based anode materials.

Keywords: In-situ generated LiAl(SiO(3))(2); Magnesiothermic reduction; Micron-sized SiO; Solid-state pre-lithiation; Ultrahigh ICE.