Ultrafast Zn2+ diffusion and exceptional stability in self-assembled 2D VS2/Ti3C2TX heterostructures for advanced zinc-ion batteries

Abstract

Vanadium disulfide (VS₂) has emerged as a promising cathode material for aqueous zinc-ion batteries (AZIBs) owing to its layered structure and high theoretical capacity. However, its practical application is hindered by limited electrical conductivity, sluggish ion diffusion kinetics, and structural degradation during long-term cycling. To overcome these challenges, we report the rational design of VS₂/Ti₃C₂T_X heterostructures synthesized via a one-step hydrothermal method, where Ti₃C₂T_X was obtained by selective etching of Al from the MAX phase Ti₃AlC₂. The enlarged interlayer spacing of Ti₃C₂T_X, coupled with the layered architecture of VS₂, enabled rapid Zn²⁺ ion insertion/extraction and improved structural stability. Benefiting from the synergistic integration of VS₂ with Ti₃C₂T_X, the heterostructure delivered a high specific capacity of 287 mA h g⁻¹ at 0.2 A g⁻¹, along with excellent cycling stability, achieving 94% capacity retention over 2000 cycles at 5 A g⁻¹. These findings highlight the critical role of MXene integration in enhancing charge transport and mechanical robustness, establishing VS₂/Ti₃C₂T_X heterostructures as high-performance cathode materials for next-generation AZIBs.