Ultrastable 1T-2H WS2 Heterostructures by Nanoarchitectonics of Phosphorus-Triggered Phase Transition for Hybrid Supercapacitors

Tungsten disulfide (WS2) has recently emerged as a nontrivial material for electrochemical applications; however, boundaries associated with its 1T and 2H phases limit its performance. Here, this issue is addressed by evolving a dual-phase 1T-2H WS2 heterostructure that combines two different phases directly on the current collector. The resulting material demonstrated a 2D transformable phase structure, large interlayer distance, and highly exposed edge-active sites. Theoretical calculations confirmed that the 1T WS2 formed after phosphorus doping exhibits a semimetallic feature, elucidating a high electronic conductivity. The edge-enriched metallic phase and interlayer engineering of the 1T-2H WS2 heterostructure validate exceptional Na+ ion intercalation. The hybrid supercapacitor cell assembled with the 1T-2H WS2 anode and Prussian blue analogue (PBA) cathode shows a specific energy of 65.5 Wh kg–1 at 784 W kg–1, and 95.7% cycling stability. This work paves a technique for phase transition and sheds light on the expansion of efficient energy storage devices.