Designing Novel Co2FeV2O8Microsticks with Prompted MultipleElectrochemical Performances for an Asymmetric Solid-StateSupercapacitor and the Hydrogen Evolution Reaction

This article reports the preparation of novel Co2FeV2O8microsticks by the solvothermal route for multiple electrochemical applicationssuch as a solid-state asymmetric supercapacitor and hydrogen evolutionreactions. The prepared microstick's physical and chemical characterizationshave been performed by X-ray diffraction (XRD), scanning electronmicroscopy (SEM), Fourier transform infrared (FTIR), transmission electronmicroscope (TEM), and X-ray photoelectron spectroscopy (XPS) to ensurethe phase purity and morphology of the material. Co2FeV2O8microsticksexhibit a specific capacity of 261 C g-1at 1 A g-1with excellent capacityretention after 10,000 cycles. Furthermore, the charge-storage contributions ofthe capacitive and diffusion-controlled process were estimated using Dunn'sapproach, and the estimation of accumulated external and internal surfacecharges was done using Trassati's approach. For practical applications, a solid-state asymmetric supercapacitor device has been fabricated, which exhibits excellent electrochemical energy storage performancesuch as an attractive specific capacity (352 C g-1), high capacitance retention for 10,000 cycles, and huge specific energy and poweroutcomes (60 Wh kg-1at 900 W kg-1). Along with the energy storage performance, the prepared Co2FeV2O8exhibits excellentelectrochemical energy conversion performance for the hydrogen evolution reactions. The electrode exhibits a low overpotential(188 mV) to generate the current density of 20 mA cm-2in 1 M KOH, and also displays excellent stability at-1.3 V for 24 h. It isconcluded that the HER of CFVO can be conducted through the Volmer-Heyrovsky mechanism with a Tafel slope of 97 mV dec-1.

Automated summary

This article reports the preparation of novel Co2FeV2O8 microsticks by the solvothermal route for multiple electrochemical applications. The microsticks exhibit excellent capacity retention and electrochemical energy storage performance. Moreover, they also demonstrate excellent electrochemical energy conversion performance for hydrogen evolution reactions.