Influence of Co-Mn mutual co-insertion in physicochemical properties of vanadate compounds for energy storage systems

Abstract

Recent advancements have led to the development of multivalent metal-ion hybrid capacitors as innovative systems for electrochemical energy storage. These devices merge the benefits of multivalent metal-ion batteries with supercapacitors, boasting impressive rate capabilities, high energy densities, significant power outputs, and exceptionally long cycle lives. In this context, Co₂V₂O₇ (CVO), Mn₂V₂O₇ (MVO), CoMnV₂O₇ (CM), Co_1.5Mn_0.5V₂O₇ (C3M), and Co_0.5Mn_1.5V₂O₇ (CM3) have been synthesized for potential use as electrodes in electrochemical applications. The physicochemical characteristics are performed by several techniques, including X-ray diffraction (XRD), Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Fourier transform Infra-red (FT-IR). The XRD data examine crystallite size, micro-strain, and dislocation density. The electrochemical characteristics of the studied materials are examined using cyclic voltammetry (CV), galvanostatic charge and discharge (GCD), and electrochemical impedance spectroscopy (EIS) in 1 M of KOH electrolyte. The obtained data suggests the pseudo pseudocapacitive nature of all the investigated electrodes with specific capacitance values between 309 and 356.2 F/g for prepared samples. Therefore, employing the synergistic effect of multiple metal ions presents an alternative approach for creating high-performance electrode materials for supercapacitors. Symmetric coin cell (SCVO) was fabricated using CVO, and gives specific capacitance 142.1 F/g, with cycling stability 95.1 % after 5000 cycles.