Hexagonal <scp> NiCo ₂ O ₄ </scp> –Polypyrrole nanocomposites as high‐performance electrodes for advanced supercapacitors

Abstract The development of pseudocapacitive electrodes that integrate bimetallic oxides with polymeric redox centers represents a promising direction for advanced energy‐storage systems. Here, we present an interfacial integrated hexagonal‐like NiCo 2 O 4 /polypyrrole (H‐NiCo 2 O 4 /PPy) architecture directly grown on conductive carbon sheets through a coupled hydrothermal–electrode position route. Unlike conventional composites, the oxide nucleates within the polymer framework during oxidative polymerization, creating a continuous electron‐transport network and strongly coupled redox interface rather than a surface‐wrapped structure. This configuration promotes efficient ion diffusion and improves electrochemical accessibility of both the bimetallic oxide and polymer redox centers. The optimized electrode exhibits high pseudocapacitive behavior with superior rate capability and cycling stability in a three‐electrode configuration, arising from the synergistic coupling between hierarchical porosity, intimate oxide–polymer interaction, and enhanced charge‐transfer kinetics. An asymmetric supercapacitor assembled with a carbon sheet counter‐electrode in 1.0 M HCl delivers a specific capacitance of 356 F/g, an energy density of 43 Wh/kg, and a power density of 5.6 kW/kg at 1.5 A g −1 , while retaining full capacitance over 100 charge–discharge cycles. This study demonstrates that controlling interfacial growth rather than merely combining components is critical for maximizing electrochemical utilization in H‐NiCo 2 O 4 /PPy systems, providing a great strategy for engineering strongly coupled bimetallic oxide–polymer electrodes for advanced energy‐storage devices.