Efficient implementation of kilogram-scale, high-capacity and long-life Si-C/TiO2 anodes

Abstract

High-performance silicon-carbon (Si-C) anodes have drawn extensive attention for next-generation high-energy lithium-ion batteries (LIBs). However, it is challenging to develop an easily scalable but effective strategy for fabricating Si-C composites to address the issues of low tap density, low initial coulombic efficiency (ICE), and poor interfacial compatibility. Here, a scalable method has been developed to fabricate kilogram-scale graphite-Si-C/TiO2 composites (GSCT) consisted of Si nanoparticles tightly fixed on the micron-graphite skeleton covered with a thin C/TiO2 layer via liquid-phase self-assembly combined with mechanical fusion and solid-phase sintering treatment. Benefiting from the structural and compositional merits, the as-obtained GSCT-c anode can deliver high ICE values of 80-83% and the tap density of 0.82 g cm−3, and achieve a high reversible capacity of 919.8 mAh g−1 even for 900 cycles at 800 mA g−1, outperforming many reported Si-C anodes. Substantial experimental characterizations and electrochemical investigations clearly unveil that the interface compatibility and structure stabilization mechanism induced by trace TiO2 incorporation and carbon coating, accounting for high-capacity and stable cycling performance. Furthermore, the assembled pouch full cells of GSCT-c||NCM622 delivered stable cycling performance and high energy density of 288.4 Wh kg−1, offering valuable material design concepts for further development in Si-C based anodes.