Effects of hydrogen etching on MnO2 electrode materials for supercapacitors

Manganese dioxide (MnO2) has received widespread attention as electrode materials in supercapacitors. In this work, the effects of hydrogen etching on MnO2 deposited on nickel foam are studied. The specific capacitance before hydrogen etching is 400 F/g and goes up to 900 F/g at a current density of 2 A/g after hydrogen etching for 5 min. After 2000 operating cycles, the capacitance retention rate of the hydrogen-etched sample is 92% compared to 82% of the untreated sample. Hydrogen etching produces surface damage and defects such as many nanopores which enhance the capacitance properties. First-principles calculation confirms the experimental results indicating that the improved performance stems from the larger specific surface area on MnO2 as well as stable defects created by hydrogen etching. The study demonstrates a simple and effective way to improve the properties of electrodes in supercapacitors.

Automated summary

The study reveals that MnO2 electrodes treated with hydrogen etching exhibit higher specific capacitance and better capacitance retention rate after cycling. Hydrogen etching causes surface damage and defects, leading to enhanced electrode performance.