Constructing yolk@multi-shell free-standing anodes with porous carbon tube and SnS2 nanosheets for Si-based lithium-ion batteries

Abstract

Silicon-based (Si-based) materials with high specific capacity are driving the electric vehicle industry and the power storage market. However, poor electrical conductivity and volume expansion during cycling limit its further application. Rational structural designs and specific material selections can be used to create robust volume buffer structures and conductive networks, which consequently contribute to the electrochemical performance of Si materials. Herein, Si particles were encapsulated in the hollow tubular carbon fiber (HT). Further, the porous carbon layer and SnS₂ nanosheets were hierarchically assembled on the surface of fibers to create free-standing films with a yolk@multi-shell structure. The unique yolk@multi-shell structure provides sufficient reserved cavities, porous structure, and multiple buffers to significantly resist volume changes. The final electrode is endowed with a multi-dimensional integrated conductive structure by HT and SnS₂ nanosheets, which greatly improves the poor conductivity of Si-based electrodes. Finally, the free-standing films can be used directly as anodes, achieving a high specific capacity of 1513.6 mAh g^–1 after 100 cycles at 0.1 A g^–1. Additionally, the assembled full cell showed 331.4 mAh g^–1 after 100 cycles at 0.2 A g^–1, which contributes significantly to the advancement of power electronics technology.