In-situ constructed NiCo2O4/NiCo2S4 heterostructure on hierarchical porous carbon for high-energy density supercapacitors

This work provides a reliable design paradigm for high-efficiency TMO/TMS heterostructures. • NiCo 2 O 4 and NiCo 2 S 4 are grown on porous carbon via a hydrothermal reaction. • NCO-NCS/HC-1.2 exhibits a specific capacitance of 2034.7 F g −1 at a current density of 1 A g −1 . Traditional NiCo-based oxides and sulfides are widely regarded as promising electrode materials for high-performance energy storage, attributed to their abundant multi-electron reversible redox chemistry. Nevertheless, substantial volume expansion during repeated charge-discharge cycling induces mechanical strain and disrupts ionic transport pathways, leading to kinetic hysteresis in ion diffusion. In comparison, hierarchical porous carbon features low cost and excellent electrical conductivity, making it an ideal composite matrix material. In this study, a hydrothermal method was adopted to modulate the in-situ growth of NiCo 2 O 4 and NiCo 2 S 4 on the surface of biomass-derived porous carbon, thereby constructing a series of composite materials with gradient components and interface coupling effects. Among these composites, NCO-NCS/HC-1.2 with the optimal ratio features a 3D conductive carbon network. The network promotes joint electron and ion transport, yielding a high specific capacitance of 2034.7 F g −1 at a current density of 1 A g −1 . The asymmetric supercapacitor achieved an energy density of 54.3 Wh kg −1 at a power density of 1066.7 W kg −1 and still maintained an energy density of 26.3 Wh kg −1 at an ultra-high power density of 21,333.3 W kg −1 . This hierarchical heterostructure strategy provides a universal design paradigm for developing high-energy-density supercapacitor. Download: Download high-res image (172KB) Download: Download full-size image