Self-assembling hierarchical NiCo2O4/MnO2 nanosheets and MoO3/PPy core-shell heterostructured nanobelts for supercapacitor

•A novel low-cost high-performance aqueous asymmetric device was designed.•The device presents a maximum energy/power densities of 60.4 Wh kg−1 and a 2400 W kg−1.•The capacitance of the device can still maintains 88.2% after 10,000 cycles.

A high energy/power density aqueous asymmetric supercapacitor device is assembled by self-assembled NiCo2O4/MnO2 composite as a positive electrode and MoO3@PPy composite as a negative electrode in Na2SO4 electrolyte. Due to the synergistic effect of electronic conductivity of PPy and high-rate metal oxides, the heterostructure electrodes reveal better charge transport and cycling stability. The overall areal capacitance retentions for the NiCo2O4/MnO2 and MoO3@PPy electrode materials are 97.5% and 86.2% after 6000 cycles, respectively. Such unique nanoarchitecture in the hybrid device further presents remarkable electrochemical performance with high capacitance and ideal cycle life at high rates. The novel device with an expanded operating voltage window of 1.6 V, presents a high energy density of 60.4 Wh kg−1 and a maximum power density of 2400 W kg−1. The device demonstrates a good cycle life with 88.2% capacitance retention after 10,000 cycles. This strategy for the choice provides a promising route for the next-generation device of energy storage and conversion with high energy, high power density, and long life.

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