Optimizing Fe2O3-based supercapacitor cathode with tunable surface pseudocapacitance via facile in situ vulcanization process

Fe2O3-based cathode materials show high theoretical specific capacitance and a wide potential range, but it is limited development due to poor electrical conductivity, undesired rate capacity and long-term cycling stability. Herein, we introduce the interconnected NiS/Co3S4 nanosheets grown on Fe2O3 substrate (Fe2O3@NiS/Co3S4) through a facile in situ solution vulcanization process. Because of the synergistic effect between the Fe2O3 nanoparticles and NiCo-S nanosheets and its unique three-dimensional open structure providing abundant channels and active sites, it is deeply investigated the electrochemical performances as positive material of supercapacitors. Meanwhile, the electrode material exhibits specific capacity of 1213.7 F g(-1) at 1 A g(-1), about 64.7% capacity retention at 10 A g(-1) and steady cycling performance about 85.2% retention after 5000 cycles at 5 A g(-1). Finally, an asymmetric supercapacitor was assembled based on Fe2O3@NiS/Co3S4 and active carbon as the positive and negative electrodes. The energy density is 43.8 Wh kg(-1) at the power density of 810 W kg(-1). At the same time, 92.4 % capacitance retention after 10,000 cycles at 5 A g(-1) was obtained.

Automated summary

By growing interconnected NiS/Co3S4 nanosheets on Fe2O3 substrate via an in situ solution vulcanization process, Fe2O3@NiS/Co3S4 shows promising electrochemical performances as a positive material of supercapacitors, with high specific capacitance, cycling stability, and retention after cycles.