Designing Novel Co_2FeV_2O_8 Microsticks with Prompted Multiple Electrochemical Performances for an Asymmetric Solid-State Supercapacitor and the Hydrogen Evolution Reaction

摘要

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.