MXene-derived TiO2 nanosheets/rGO heterostructures for superior sodium-ion storage

Abstract

Transition metal oxides hold promise as electrode materials for energy-storage devices such as batteries and supercapacitors. However, achieving ideal electrode materials with high capacity, long-term cycling stability, and superb rate capability remains a challenge. In this study, we present a self-assembled heterogeneous structure consisting of TiO2 nanosheets derived from Ti3C2Tx MXene and reduced graphene oxide. This structure facilitates the formation of heterogeneous structures while establishing a conductive network. The restacking of porous TiO2 nanosheets and reduced graphene oxide within the heterostructure results in high porosity and excellent conductivity. Due to enhanced electron and Na+ transfer, as well as improved structural stability during the Na+ insertion/extraction process, this heterogeneous structure exhibited exceptional Na+ storage performance. Specifically, it exhibits a long-term cycling stability (217 mAh g−1 at 10 C, 5000 cycles) and an ultrahigh rate capability (135 mAh g–1, 40 C). Analysis of electrode reaction kinetics suggests that Na+ storage in the heterostructure is predominantly governed by a surface-controlled process. Our results provide a promising strategy for utilizing self-assembled heterostructures in advanced energy storage applications.

Keywords

• Ti3C2Tx MXene
• Titanium dioxide
• Self-assembly
• Heterostructure
• Sodium-ion batteries