Flexible 3D hierarchical porous NiCo2O4/CC electrode decorated by nitrogen-doped carbon from polyaniline carbonization for high-performance supercapacitors

Abstract

Atomic doping is considered as an effective method to prepare high-active conductivity-improved electrochemical materials. We report the utilization of a three-dimensional hierarchical porous nitrogen-doped carbon–NiCo2O4/CC as the flexible supercapacitor electrodes and recycled biosensor. In a hydrothermal process, three-dimensional hierarchical needle-like NiCo2O4/CC arrays were prepared by one-step, which changed to the mulberry-like morphology after in situ deposition of polyaniline nanoparticles on NiCo2O4/CC. Upon polyaniline carbonization at high temperature, the resulting porous nitrogen-doped carbon–NiCo2O4 showed uniform nanorod networks and dramatic improvements in the electrolyte affinity, penetration and ionic motion. The obtained electrodes display good flexibility and large areal specific capacitance of 3.0 F cm−2 (2520 F g−1) at the current density of 1.0 mA cm−2, with energy density of 171.5 Wh kg−1 and power density of 1118.4 W kg−1. After 10000 cycles, the capacitance retention rate reaches 90.79%. The prepared NiCo2O4-based composites display design novelty and promising applications in the flexible supercapacitors with large capacitance and high stability.