Enriched supercapacitive performance of electrochemically tailored β-Co(OH)2/CoOOH nanodiscs from sacrificial Co3(PO4)2·4H2O microbelts

Abstract

Electrochemically induced structural reconstruction process of metal precursors into their corresponding metal hydroxides/(oxy)hydroxides is developed as an ingenious strategy towards preparing efficient electrode material. However, the influence of electrochemical activation on the charge storage ability of electrode material is barely explored. Herein, we have utilized a synthetic strategy (solvothermal reaction in water:ethanol mixture) to prepare Co3(PO4)2·4H2O microbelts and subsequently applied the electrochemical bulk reconstruction process in 1 M KOH electrolyte. A thorough physical and electrochemical characterization unveil that the electrode material is converted into redox active site rich β-Co(OH)2/CoOOH nanodiscs via etching of lattice anionic PO43− moieties. The material possesses a specific capacitance of 386 F g−1at a current density of 0.25 A g−1. Additionally, a hybrid device constructed with β-Co(OH)2/CoOOH nanodiscs and activated charcoal (AC) as positive and negative electrodes has achieved a high energy density of 13.33 Wh Kg−1at a power density of 400 W kg−1. Further, the device displayed a good capacitance retention of 93 % (columbic efficiency ~98 %) up to 10,000 cycles. The improved charge storage of reconstructed material with abundant redox active sites could be attributed to the facile diffusion of electrolyte ions into the bulk of the material. © 2024 Elsevier Ltd