High power and stable P-doped yolk-shell structured Si@C anode simultaneously enhancing conductivity and Li+ diffusion kinetics

Silicon is a low price and high capacity anode material for lithium-ion batteries. The yolk-shell structure can effectively accommodate Si expansion to improve stability. However, the limited rate performance of Si anodes can't meet people's growing demand for high power density. Herein, the phosphorus-doped yolk-shell Si@C materials (P-doped Si@C) were prepared through carbon coating on P-doped Si/SiOx matrix to obtain high power and stable devices. Therefore, the as-prepared P-doped Si@C electrodes delivered a rapid increase in Coulombic efficiency from 74.4% to 99.6% after only 6 cycles, high capacity retention of similar to 95% over 800 cycles at 4 A.g(-1), and great rate capability (510 mAh.g(-1) at 35 A.g(-1)). As a result, P-doped Si@C anodes paired with commercial activated carbon and LiFePO4 cathode to assemble lithium-ion capacitor (high power density of similar to 61,080 W.kg(-1) at 20 A.g(-1)) and lithium-ion full cell (good rate performance with 68.3 mAh.g(-1) at 5 C), respectively. This work can provide an effective way to further improve power density and stability for energy storage devices.

Automated summary

Phosphorus-doped yolk-shell Si@C materials were prepared to improve the stability and power of silicon anodes, resulting in increased Coulombic efficiency, high capacity retention, and great rate capability. Pairing these anodes with commercial activated carbon and LiFePO4 cathode led to the assembly of high power density lithium-ion capacitor and lithium-ion full cell, showing good rate performance. This work provides an effective way to further enhance power density and stability in energy storage devices.