Electrochemical performance of Bi2O3 supercapacitors improved by surface vacancy defects

Vacancy defects have important impacts on the physical-chemical properties of metal oxides. In the present work, two types of Bi2O3 powders with different morphologies were synthesized for supercapacitor electrodes by calcination (denoted as c-Bi2O3) and two-step hydrothermal methods (donated as h-Bi2O3). Vacancy clusters of VBi‴VO··VBi‴ with different concentrations were observed in these two samples by positron annihilation lifetime...