MXene-Supported Vanadium Sulfide Composites Reinforced by Tailored Carbon Nanotube Networks for High-Performance Supercapattery

The strategic engineering of multidimensional electrode materials is essential for next-generation hybrid energy storage systems, specifically supercapatteries, which integrate the high energy density of batteries and high-power density of supercapacitors. A rationally engineered composite comprising vanadium sulfide (VS₄) nanosheets uniformly anchored onto 2D MXene (Ti₃C₂T_x) sheets through a facile solvothermal method, further reinforced with carbon nanotubes (CNTs) to construct a 3D conductive network, is demonstrated. The uniform dispersion of VS₄ on MXene, facilitated by strong V─C interfacial bonding, mitigates MXene restacking, enhances electrical conductivity, and stabilizes the hybrid structure. Meanwhile, CNTs further improve electron mobility, reduce particle aggregation, and reinforce mechanical strength. This multidimensional design significantly boosts redox kinetics and cycle stability. The optimized VS₄-MXene-CNT electrode delivers a high specific capacity of 802.46 C g⁻¹ (1337.44 F g⁻¹) at 0.3 A g⁻¹ in 6 M KOH, retaining 97% capacitance after 5000 cycles. The fabricated asymmetric supercapattery device (ASD) exhibits a specific capacity of 148.18 C g⁻¹ (246.97 F g⁻¹) at 0.3 A g⁻¹, achieving specific energy of 12.35 Wh kg⁻¹ and specific power of 1856.43 W kg⁻¹, with 93% capacitance retention over 5000 cycles. This work offers a promising route toward designing for durable, high-performance supercapattery electrodes.