Interconnected TiOx/carbon hybrid framework incorporated silicon for stable lithium ion battery anodes

Abstract

Silicon is one of the most promising anode materials for lithium ion batteries due to its high-specific capacity. However, its poor cycling stability and rate capability limit its practical use. Herein, we report the scalable fabrication of a unique three-dimensional porous silicon/TiO_x/carbon (Si/TiO_x/C, 0 < x < 2) binder free composite electrode for lithium ion batteries. The TiO_x/C frameworks were incorporated by a slurry coating method followed by heat treatment, resulting in a well-connected three dimensional framework structure consisting of Si nanoparticles conformably embedded in the conducting TiO_x/C matrix. The porous TiO_x/C conductive framework effectively alleviates the volume change of Si during cycling and substantially improves the structural stability of electrode materials. Moreover, the amorphous TiO_x/C conductive matrix provides high electrical conductivity and facilitates the electrochemical reaction between Li and Si. As a consequence, the Si/TiO_x/C electrode exhibits a stable reversible specific capacity of 1696 mA h g⁻¹ at 0.1 A g⁻¹ after 100 cycles with 87% capacity retention and superior rate capability (754 mA h g⁻¹ at 15 A g⁻¹). The exceptional performance of the Si/TiO_x/C electrode combined with the facile synthesis technique makes it promising for high energy lithium ion batteries.