Insight into defect-engineered gallium oxynitride nanoparticle-based electrodes with improved electrochemical performance for supercapacitors

Gallium oxynitride (GON) with phase resembling that of wurtzite gallium nitride (GaN) is a promising electrode material for supercapacitors. However, pristine GON nanoparticles exhibit relatively low specific capacitance, limiting their wide application in energy storage systems. In this paper, we report on dramatic increase in electrochemical performance of GON nanoparticle-based electrodes through purposefully introducing both cation and anion defects in the electrodes via controllable electrochemical etching. The textural property, band structure, and defect concentration of the electrodes can be engineered by altering the etching time. The functions of both cation and anion defects on the electrode performance have been clarified on the basis of experimental and theoretical computation results. The enhanced electrochemical performance for the etched electrodes is attributed to (i) elimination of the surface oxide layer; (2) improved specific surface area (S-BET) and pore volume (V-pore); and (iii) engineered cation and anion defects. It is the synergistic effect of cation and anion defects, rather than S-BET and V-pore, that determines the electrochemical performance of the electrodes. The GON nanoparticle-based electrodes with engineered defects have potential application in supercapacitors. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This paper reports on the significant improvement in electrochemical performance of gallium oxynitride (GON) nanoparticle-based electrodes by introducing both cation and anion defects via controllable electrochemical etching. The textural property, band structure, and defect concentration of the electrodes can be engineered by altering the etching time. The enhanced electrochemical performance is attributed to the elimination of surface oxide layer, improved specific surface area and pore volume, as well as engineered cation and anion defects.