Graphene wrapped silicon suboxides anodes with suppressed Li-uptake behavior enabled superior cycling stability

Silicon based anodes are prospective candidates for high energy density lithium ion batteries, but suffer from large volume expansion during cycling which leads to rapidly capacity fading. This work proposes a self-mechanical inhibition mechanism to restrict intrinsic Li-uptake in silicon suboxides (SiO) anode with graphene wrapping, and accordingly develops SiO/graphene/C composite anodes with superior cycling stability. The composite anode containing 19 wt% graphene, owing to interaction stress between SiO and graphene during lithiation reactions, behaves only 86% Li-uptake based on SiO itself, delivers 1244 mAh g(-1) reversible capacity at 0.05C, displays merely 67% volume expansion ratio (113% for SiO@C anode) after full lithiation and shows 86.2% capacity retention (44.9% for SiO@C anode) after 500 cycles at 1C. A 26.3 Ah pouch cell prepared with Ni-rich cathode and SiO/graphene/C blended graphite anode achieves energy density of 353 Wh kg(-1) at 2.8-4.3 V and displays 78.1% capacity retention after 500 cycles at 0.2C.

Automated summary

This study developed a SiO/graphene/C composite anode with self-mechanical inhibition mechanism to restrict intrinsic Li-uptake, improving cycling stability. The composite anode exhibited superior performance in cycling stability, volume expansion, and capacity retention compared to traditional SiO@C anode.