A multilayered sturdy shell protects silicon nanoparticle Si@void C@TiO2 as an advanced lithium ion battery anode

Abstract

Nowadays with the increasing demand for lithium-ion batteries (LIBs), the high-capacity silicon anode is becoming a promising electrode material. However, the huge expansion of silicon during long cycling remains a significant challenge. Herein, a functional double layer Si-based multi-component structure Si@void C@TiO₂ was designed as anode material for lithium-ion batteries. This structure has a void space inside and a double shell composed of carbon layer and crystalline TiO₂ outside, which not only takes effective in improving electric conductivity of the Si electrode material, but also maintains the structural stability and integrity of the electrode. The layers impede the electrolyte from contacting with Si, contributing to forming a stable SEI film and providing high Coulombic efficiency. Therefore, the Si@void C@TiO₂ electrode provides a high reversible capacity of 1251 mA h g⁻¹, and stable long cycling with a capacity of 668 mA h g⁻¹ over 500 cycles at a current density of 100 mA g⁻¹, and 98% average Coulombic efficiency, making this potential superior material Si-based multi-component anode a high-performance electrode material for Li-ion batteries.