Chemical reduction-induced defect-rich bismuth oxide-reduced graphene oxide anode for high-performance supercapacitors

[Display omitted] •Defectivation of Bi2O3 and compositing with rGO is simultaneously realized by a one-step reducing method.•The Bi2O3-rGO-100 anode exhibits a high specific capacitance of 1053F/g at 1 A/g.•The Ni3Co2-rGO//Bi2O3-rGO-100 battery-type pouch-cell supercapacitor achieves an energy density of 118.5 Wh kg−1 at a power density of 850 W kg−1.•Two series-connected pouch-cell supercapacitor successfully illuminate 88 LED lamps for 12 min. We prepare bismuth oxide-reduced graphene oxide (Bi2O3-rGO) composite anode using a one-step chemical precipitation/reduction method. Under a reducing atmosphere, oxygen atoms on the surface of Bi2O3 are gradually removed and neighboring oxygen atoms migrate to the surface, leaving oxygen vacancies. Defective Bi2O3 enhances the number of active sites, providing additional pseudocapacitive performance. The transition metal oxide-based Bi2O3 acts as an anode, providing capacitive performance that far exceeds that of conventional carbon materials. Moreover, the introduction of rGO forms a conductive network for Bi2O3, improving capacitive contribution and ion diffusion capabilities for the electrode. The Bi2O3-rGO-100 (GO added at 100 mg) exhibits a high specific capacitance of 1053F/g at 1 A/g, significantly higher than that of Bi2O3 (866F/g). The Bi2O3-rGO-100 anode and Ni3Co2-rGO cathode are assembled into a battery-type supercapacitor. The coin-cell device achieves an energy density of 88.2 Wh kg−1 at a power density of 850 W kg−1. The Ni3Co2-rGO//Bi2O3-rGO-100 pouch-cell device demonstrates an extremely low Rct of 0.77 Ω. At a power density of 850 W kg−1, the energy density reaches 118.5 Wh kg−1, and remains 67.4 Wh kg−1 at 8500 W kg−1.