Metallic 1T Phase Induced Hierarchical 2H-1T WS2/MoO3/CNT Nanoflowers for Hybrid Supercapacitor Applications

Abstract

The design of hybrid supercapacitors is fundamentally challenged by the mismatch in charge storage kinetics between Faradaic and capacitive electrodes, poor interfacial compatibility, and structural instability during long-term cycling. To address these issues, a hydrothermally synthesized 2H-1T WS2/MoO3/CNT nanocomposite was developed as an efficient electrode material by tailoring the morphological, structural, and electronic properties of WS2 through CNT-derived conductive pathways and MoO3-mediated redox modulation. This strategy resulted in a hierarchical nanoflower heterostructure with stabilized mixed 2H-1T phases and abundant electrochemically active sites, as verified by Rietveld refinement, XPS, BET, and electron microscopy, thereby providing an efficient framework for rapid ion/electron transport and balanced EDLC/Faradaic charge storage. Consequently, the WS2/MoO3/CNT electrode exhibited hybrid charge storage behavior, delivering a high specific capacitance of 905 F g–1 at 1 A g–1, significantly outperforming WS2/MoO3 (605 F g–1) and pristine WS2 (280 F g–1). The enhanced electrochemical performance was associated with reduced charge-transfer and diffusion resistances, facilitating efficient charge transport and contributing to excellent cycling stability, with 93.2% capacitance retention after 8000 cycles at 12 A g–1. The WS2/MoO3/CNT symmetric hybrid cell delivered an energy density of 53.7 Wh kg–1 at a power density of 0.8 kW kg–1 under a 1.6 V operating voltage window, along with excellent cycling stability, retaining 96.8% of its initial capacitance over 8000 cycles. Postcycling characterization confirmed the preservation of the phase composition, crystal structure, and morphology after 8000 cycles, while the assembled coin cell demonstrated practical feasibility by successfully powering an LED and a wristwatch. These findings highlight the potential of the engineered 2H-1T WS2/MoO3/CNT heterostructure as a promising electrode material for high-performance hybrid supercapacitors.