Flexible zinc ion hybrid supercapacitors enabled by N/S co-doped porous carbon and bacterial cellulose/ZnSO4 electrolyte

Zinc-ion hybrid capacitors (ZHSCs), as a novel energy storage devices with battery type anode, capacitive type cathode, have attached widely attention. Herein, N, S co-doping porous carbon (NSC) is synthesized by a salt template assisted freeze drying method. Bacterial cellulose (BC)/ZnSO4 electrolyte is prepared by impregnating BC membrane into ZnSO4 solution. Thanks to significant cathode material, favorable flexible electrolyte system, and rational device design, the flexible Zn//BC/ZnSO4//NSC ZHSC device presents excellent electrochemical performance, including an excellent specific capacity of 113 mA h g-1 and a high energy density of 90.8 W h kg-1 at 0.5 A g-1, a superior cycling stability with excellent capacity retention of 93.9% over 10000 cycles at 5 A g-1. Impressively, NSC-6 based ZHSC device shows similar capacitive behavior under various bending states, demonstrating its excellent flexibility and stability. Overall, the ZHSC devices based on NSC cathode and BC/ ZnSO4 flexible electrolyte are promising to be applied in portable, flexible, and wearable electronics.

Automated summary

The researchers synthesized N, S co-doping porous carbon using a salt template assisted freeze drying method and prepared a flexible Zn//BC/ZnSO4//NSC ZHSC device with excellent electrochemical performance. The device showed a specific capacity of 113 mA h g-1, a high energy density of 90.8 W h kg-1, and a superior cycling stability with excellent capacity retention of 93.9% over 10000 cycles at 5 A g-1. The flexible ZHSC device based on NSC cathode and BC/ZnSO4 flexible electrolyte shows promising application potential in portable, flexible, and wearable electronics.