3D Porous Honeycomb-Like CoN-Ni₃N/N-C Nanosheets Integrated Electrode for High-Energy-Density Flexible Supercapacitor

Transition metal nitrides (TMNs) are considered as potential electrode materials for high-performance energy storage devices. However, the structural instability during the electrochemical reaction process severely hinders their wide application. A general strategy to overcome this obstacle is to fabricate nanocomposite TMNs on the conducting substrate. Herein, the honeycomb-like CoN-Ni3N/N-C nanosheets are in situ grown on a flexible carbon cloth (CC) via a mild solvothermal method with post-nitrogenizing treatment. As an integrated electrode for the supercapacitor, the optimized CoN-Ni3N/N-C/CC achieves remarkable electrochemical performance due to the enhanced intrinsic conductivity and increased concentration of the active sites. In particular, the flexible quasi-solid-state asymmetric supercapacitor assembled with CoN-Ni3N/N-C/CC cathode and VN/CC anode delivers an excellent energy density of 106 mu Wh cm(-2), maximum power density of 40 mW cm(-2), along with an outstanding cycle stability. This study provides a neoteric perspective on construction of high-performance flexible energy storage devices with novel metallic nitrides.