Electrochemical performances of reduced graphene oxide/titanium dioxide composites for sodium-ion batteries

Abstract

Anatase TiO 2 shows excellent long-term cycling stability as an anode for sodium-ion batteries. However, the low specific capacity and poor rate capability resulting from its intrinsic low electrical conductivity limit its applications. In this work, TiO 2 nanoparticles were coated with reduced graphene oxide (RGO) using a combination of spray-drying and heat treatment. Electrochemical tests showed that the obtained RGO/TiO 2 composites had improved electrochemical performances. The reversible capacities of the RGO/TiO 2 [4.0% (w)] composites were 183.7 mAh∙g -1 (20 mA∙g -1), 153.7 mAh∙g -1 (100 mA∙g -1), and 114.4 mAh∙g -1 (600 mA∙g -1). Bare TiO 2 showed low capacities of 93.6mAh∙g-1 (20mA∙g-1), 69.6mAh∙g-1 (100mA∙g-1), and 26.5mAh∙g-1 (600 mA∙g -1). The 4.0%(w) TiO 2 /RGO composites exhibited good cycling stability with a charge capacity of 146.7 mAh∙g -1 at a current density of 100 mA∙g -1 after 350 cycles, compared with 68.8 mAh∙g -1 for bare TiO 2. RGO modification is a promising method for improving the electrochemical performances of the sodium energystorage materials.