Scalable synthesis of silicon-nanolayer-embedded graphite for high-energy lithium-ion batteries

Existing anode technologies are approaching their limits, and silicon is recognized as a potential alternative due to its high specific capacity and abundance. However, to date the commercial use of silicon has not satisfied electrode calendering with limited binder content comparable to commercial graphite anodes for high energy density. Here we demonstrate the feasibility of a next-generation hybrid anode using silicon-nanolayer-embedded graphite/carbon. This architecture allows compatibility between silicon and natural graphite and addresses the issues of severe side reactions caused by structural failure of crumbled graphite dust and uncombined residue of silicon particles by conventional mechanical milling. This structure shows a high first-cycle Coulombic efficiency (92%) and a rapid increase of the Coulombic efficiency to 99.5% after only 6 cycles with a capacity retention of 96% after 100 cycles, with an industrial electrode density of >1.6 g cm−3, areal capacity loading of >3.3 mAh cm−2, and <4 wt% binding materials in a slurry. As a result, a full cell using LiCoO2 has demonstrated a higher energy density (1,043 Wh l−1) than with standard commercial graphite electrodes. Silicon has long been recognized as a high-energy battery electrode but its commercialization faces significant barriers. Here the authors report scalable synthesis of silicon-nanolayer-embedded graphite electrodes that display cycling stability at the industrial electrode density.