Anchoring tungsten oxide nanorods on TiO2 nanowires coupled with carbon for efficient lithium-ion storage

Abstract

Reasonable construction of hierarchical electrode materials is verified as a promising way to improve the electrochemical performance due to the synergistic effect between unique components and constructions. Hence, a hierarchical nanostructure composed of tungsten oxide nanorods anchored on TiO₂ nanowires coupled with a carbon layer (TiO₂@WO_x-C NWs) was synthesized as an electrode material by exploiting the self-assembly function of dopamine and carbonization. The inner one-dimensional TiO₂ nanowires served as the stable substrate with WO_x anchored on the surface of TiO₂ NWs and the tightly coupled carbon nanosheets, which can not only facilitate electron transport but also provide more active sites for electrochemical reactions. As a result, benefitting from the synergistic effects between three functional components and the multi-dimensional hierarchical structures, the as-prepared TiO₂@WO_x-C NWs displayed excellent lithium storage performance with a specific capacity of 651.4 mA h g⁻¹ after 500 cycles at 1.0 A g⁻¹, which is superior to most Ti-based structures. The enhanced electrochemical performance is mainly attributed to the synergistic effect of the different dimensional structures, the high capacity of tungsten oxide and the surface coating of the conductive carbon material. This work provides a simple and effective approach to designing functional hierarchical structures for energy storage and conversion.