Diversified constructions and electrochemical cycling stability of metal oxide fiber supercapacitors

Rapid development of electronic technology put forward high requirements for sustainable energy storage systems, and fiber supercapacitors have been considered as one of the prospective research fields. Herein, five metal oxides of Al2O3, Fe2O3, MoO2, NiO and ZnO are chosen as electrochemical active materials to prepare fiber electrodes as well as parallel fiber supercapacitors, respectively. According to the test results, ZnO fiber supercapacitor exhibits the optimal electrochemical performance among them, achieving 1.19 μF·cm−1 at the current density of 0.25 μA·cm−1. In addition, the electrochemical performance of parallel and twisted ZnO fiber supercapacitors are compared systematically so as to illustrate the effect of device structures on their electrochemical performance, and the twisted ZnO fiber supercapacitor shows higher capacitance retention and energy density than the parallel fiber device. Furthermore, the electrochemical cycling stability of parallel as well as twisted ZnO fiber supercapacitors are studied after 10,000 galvanostatic charge–discharge cycles, and parallel ZnO fiber supercapacitor presents better cycle stability owing to the simpler device structure. This work would provide effective evidence for the design and development of high-performance metal oxide-based fiber supercapacitors in the future.