<scp>ZnO</scp>‐Coated Silicon Oxide Nano‐Anode: Synergistic Enhancement of Cycling and Thermal Stability of Lithium‐Ion Batteries
Keren Shi, Wende Yi, Weikang Su, Qiaowei Xiao, Ziyan Wang, Xiaoyu Li, Jing Mu, Wufei Tang, Zhihan Peng, Huiqin Yao
Abstract
Silicon oxide (SiO) has great potential as a high‐capacity anode for lithium‐ion batteries, but its practical use is limited by excessive volume expansion (>200%) and rapid capacity fade, especially at high temperatures. Traditional strategies, like carbon coating and nanostructuring, only partially address these issues. This study introduces a novel approach by synthesizing porous SiO microspheres encapsulated within a conformal ZnO shell (MS‐ZnO). The internal porosity absorbs volumetric strain, while the ZnO shell provides mechanical stability, preventing electrode disintegration. MS‐ZnO (M‐Z: Zinc oxide coating on SiO) shows significantly reduced swelling (32.4% vs 94.8% for ZnO unmodified SiO (P‐M)) and a high reversible capacity of 978.65 mAh g −1 after 500 cycles, double that of unmodified SiO. At 90 °C, MS‐ZnO maintains a stable Coulombic efficiency of ~75%, compared with ~32% for unmodified SiO, indicating excellent thermal stability. In full‐cell tests with LiFePO 4 , MS‐ZnO delivers 151 mAh g −1 at 0.2C with 83.5% capacity retention after 100 cycles. GITT and DFT analysis reveal that the ZnO shell enhances Li + diffusion and mechanical strength. This work presents ZnO encapsulation as a transformative strategy to overcome volume change and thermal instability, unlocking the potential of SiO anodes for high‐performance, high‐safety lithium‐ion batteries.