Enhancing Lithium-Ion Batteries with a 3D Conductive Network Silicon–Carbon Nanotube Composite Anode
Yuru Wang, Yuru Wang, Zhihua Zeng, Yong Liu, Gang Huang, Pan Zhang, Xiaodong Ma, Fan Gao, Ziqiang Zhang, Ye Wang, Ye Wang, Yanqing Wang, Yanqing Wang
Abstract
To meet the rising demand for energy storage, high-capacity Si anode-based lithium-ion batteries (LIBs) with extended cycle life and fast-charging capabilities are essential. However, Si anodes face challenges such as significant volume expansion and low electrical conductivity. This study synthesizes a porous spherical Si/Multi-Walled Carbon Nanotube (MWCNT)@C anode material via spray drying, combining Si nanoparticles, MWCNT dispersion, sucrose, and carboxymethyl cellulose (CMC). The MWCNT incorporation creates a robust 3D conductive network within the porous microspheres, enhancing Li + diffusion and improving fast-charging/discharging performance. After 300 cycles at 1 A g –1, the material achieved a discharge capacity of 536.6 mA h g –1 with 80.5% capacity retention. Additionally, integrating a 3D network of Single-Walled Carbon Nanotubes (SWCNTs) further enhanced capacity retention in a binder-free, self-supporting electrode created through vacuum filtration. The Si/MWCNT@C//LiFePO 4 full cell exhibited an initial Coulombic efficiency (ICE) exceeding 80%, with a specific capacity of 72.4 mA h g –1 and 79.8% capacity retention after 400 cycles at 1 A g –1 . This study offers a promising strategy for improving the performance and structural design of Si anodes.