Mechanically Reinforced Localized Structure Design to Stabilize Solid–Electrolyte Interface of the Composited Electrode of Si Nanoparticles and TiO<sub>2</sub> Nanotubes
Mingzheng Ge, Yuxin Tang, Oleksandr I. Malyi, Yanyan Zhang, Zhiqiang Zhu, Zhisheng Lv, Xiang Ge, Huarong Xia, Jianying Huang, Yuekun Lai, Xiaodong Chen
Abstract
Abstract Silicon anode with extremely high theoretical specific capacity (≈4200 mAh g −1 ), experiences huge volume changes during Li‐ion insertion and extraction, causing mechanical fracture of Si particles and the growth of a solid–electrolyte interface (SEI), which results in a rapid capacity fading of Si electrodes. Herein, a mechanically reinforced localized structure is designed for carbon‐coated Si nanoparticles (C@Si) via elongated TiO 2 nanotubes networks toward stabilizing Si electrode via alleviating mechanical strain and stabilizing the SEI layer. Benefited from the rational localized structure design, the carbon‐coated Si nanoparticles/TiO 2 nanotubes composited electrode (C@Si/TiNT) exhibits an ideal electrode thickness swelling, which is lower than 1% after the first cycle and increases to about 6.6% even after 1600 cycles. While for traditional C@Si/carbon nanotube composited electrode, the initial swelling ratio is about 16.7% and reaches ≈190% after 1600 cycles. As a result, the C@Si/TiNT electrode exhibits an outstanding capacity of 1510 mAh g −1 at 0.1 A g −1 with high rate capability and long‐time cycling performance with 95% capacity retention after 1600 cycles. The rational design on mechanically reinforced localized structure for silicon electrode will provide a versatile platform to solve the current bottlenecks for other alloyed‐type electrode materials with large volume expansion toward practical applications.