Synthesis of Bi2O3/hierarchical porous carbon composites for supercapacitor application

Bismuth oxide (Bi2O3) is considered a promising electrode material for supercapacitors boasting a high theoretical capacity. Its weak conductivity, limited rate performance, and poor cycling stability have significantly hindered practical applications. In this work, a simple precipitation and calcination method was used to prepare Bi2O3/hierarchical porous carbon composite materials (Bi2O3/N-HPC). The biomass-derived hierarchical porous carbon precursor was prepared through a process involving nitrogen doping and chemical activation. Comprehensive physical and chemical structure characterization results showed that a large number of spherical Bi2O3 particles were dispersed on the surface of the carbon material, providing numerous active sites for electrochemical reactions. The nitrogen-doped hierarchical porous carbon scaffold provided rapid pathways for charge transfer and restricted the aggregation of Bi2O3 particles. As an electrode material in a 6 M KOH electrolyte, Bi2O3/N-HPC exhibited a specific capacitance of 684.9 F g−1 at a current density of 0.5 A g−1, and even at an increased current density of 20 A g−1, the specific capacitance remained at 500.0 F g−1. After 10,000 cycles of charge and discharge, the capacitance retention rate of the Bi2O3/N-HPC electrode reached 85.2 %. This research offers a promising pathway for the development of high-performance supercapacitor electrode materials.