Interfacial nanoarchitectonics of SiOx via CVD carbon coating and vapor-phase polymerized PEDOT for enhanced lithium-ion battery anode performance

Background: Thanks to the high theoretical capacity, silicon oxides (SiOx) hold great potential as anode materials for the next-generation high-performance lithium-ion batteries (LIBs). However, the low conductivity and substantial volume fluctuations of SiOx result in significant polarization and rapid capacity fading, greatly hindering its electrochemical performance and practical application. Methods: To overcome the inherent challenges of SiOx, herein, a dual surface modification consisting of a carbon layer and conducting polymer layer is coated on SiOx. The process involves chemical vapor deposition (CVD) with C2H2 as the carbon source, followed by vapor-phase polymerization (VPP) to form high-quality carbon and poly(3,4-ethylenedioxythiophene) (PEDOT) layers on SiOx. Significant findings: The dual-modified layers provide the resulting SiOx with enhanced electrical conductivity and improved structural stability. The modified SiOx demonstrates a high charge capacity of 1660.1 mAh/g at 0.1C, remarkable rate performance with the charge capacity of 945.0 mAh/g at 3C, and superior cycling span (similar to 812.7 mAh/g over 200 cycles). In addition, the modified SiOx demonstrates excellent compatibility with conventional graphite (GP) anode material, significantly enhancing its electrochemical performance.