Boosting redox kinetics in CoS/Ti3C2 heterostructure via interfacial charge redistribution for high-energy-density supercapacitors

Supercapacitors are indispensable for next-generation energy storage, achieving high energy density and long-term durability remains a formidable challenge. Conventional CoS suffers from poor conductivity, while Ti 3 C 2 faces severe restacking. Herein, we report a novel synthesis strategy that integrates metal-organic framework (MOF) growth with electrostatic self-assembly to construct heterojunction of CoS nanotubes coated with ultrathin Ti 3 C 2 nanofilms. Material characterization via SEM, TEM, XRD, and XPS systematically confirms the heterostructure formation, and chemical composition. This rational design synergistically leverages CoS high pseudocapacitance and Ti 3 C 2 metallic conductivity while the heterostructure mitigates restacking, enhances charge transfer, and stabilizes interfacial interactions. Density functional theory (DFT) calculations reveal strengthened OH - adsorption at the Co-Ti interface (E ad = 1.106 eV). Consequently, the CoS/Ti 3 C 2 @CC delivers a remarkable specific capacitance of 1034.21 F g -1 at 1 A g -1 . Assembled into a supercapacitor, CoS/Ti 3 C 2 @CC//AC achieves a high energy density of 74.22 Wh kg -1 at 800 W kg -1 , maintaining 89.13% initial capacitance after 10,000 cycles. Significantly, it exhibits a remarkably low leakage current (0.23 μA) and ultra-prolonged voltage retention (47.14% after 120 h), underscoring exceptional durability. This work pioneers a rational heterostructure engineering strategy by integrating MOF-derived architectures with conductive MXene nanofilms, offering critical insights for the development of ultra-durable supercapacitor.