A flexible spiral-type supercapacitor based on ZnCo₂O₄ nanorod electrodes

Fiber electrochemical capacitors show advantages such as light weight and flexibility, and may also be easily integrated or woven into various electronic devices with low cost and high efficiency. In this work, we report the preparation of ZnCo₂O₄ nanorods on a Ni wire as the fiber electrodes, using a simple and rapid single-step hydrothermal process. The electrochemical properties of the free-standing supercapacitor were analyzed using a two electrode system. The supercapacitor achieved a specific capacitance of 10.9 F g^-1. An energy density of 76 mWh kg^-1 and a power density of up to 1.9 W kg^-1 were also obtained for the fiber supercapacitors. The flexible supercapacitor exhibited remarkable electrochemical stability when subjected to bending at various angles, illustrating the promise for use as electrodes for wearable energy storage.