Sequencing‐Dependent Impact of Carbon Coating on Microstructure Evolution and Electrochemical Performance of Pre‐lithiated SiO Anodes: Enhanced Efficiency and Stability via Pre‐Coating Strategy

作者：Si Yi, Zhilin Yan, Yiming Xiao, Zhen Wang, Cuicui Ye, Jingwen Zhang, Huangjie Qiu, Pengpeng Ning, Deren Yang, Ning Du · 发表于：Small · 年份：2024 · DOI：10.1002/smll.202403847 · 被引用次数：18 · 研究领域：Advancements in Battery Materials、Supercapacitor Materials and Fabrication、Advanced Battery Materials and Technologies

Silicon monoxide (SiO) has attracted considerable interest as anode material for lithium-ion batteries (LIBs). However, their poor initial Coulombic efficiency (ICE) and conductivity limit large-scale applications. Prelithiation and carbon-coating are common and effective strategies in industry for enhancing the electrochemical performance of SiO. However, the involved heat-treatment processes inevitably lead to coarsening of active silicon phases, posing a significant challenge in industrial applications. Herein, the differences in microstructures and electrochemical performances between prelithiated SiO with a pre-coated carbon layer (SiO@C@PLi) and SiO subjected to carbon-coating after prelithiation (SiO@PLi@C) are investigated. A preliminary carbon layer on the surface of SiO before prelithiation is found that can suppress active Si phase coarsening effectively and regulate the post-prelithiation phase content. The strategic optimization of the sequence where prelithiation and carbon-coating processes of SiO exert a critical influence on its regulation of microstructure and electrochemical performances. As a result, SiO@C@PLi exhibits a higher ICE of 88.0%, better cycling performance and lower electrode expansion than SiO@PLi@C. The pouch-type full-cell tests demonstrate that SiO@C@PLi/Graphite||NCM811 delivers a superior capacity retention of 91% after 500 cycles. This work provides invaluable insights into industrial productions of SiO anodes through optimizing the micr...