Asymmetric nickel-doped chromium molybdates (Nix Cr2 –x (MoO4)3 as high-performance anode materials for supercapacitors

Abstract

In this work, Nickel-doped Chromium Molybdates were synthesized by a convenient, cost-effective, and good-yield co-precipitation process for supercapacitor electrodes. Morphological and structural characterizations of materials were carried out by using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and Raman spectroscopy. The electrochemical performance was evaluated by performing cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. Based on the synergistic effect of both Ni (II) and Cr (III) ions, specific capacitance increases with the doping of nickel until the parent lattice structure is maintained. The material with a nickel dopant concentration of 0.15 delivered the highest specific capacitance of 1572 F/g at 1 A/g among all other materials, good cyclic stability, and 100% coulombic efficiency. Moreover, the detailed kinetic analyses suggested that the dominance of the diffusion-controlled charge storage mechanism is responsible for the high specific capacitance of the materials. The present study demonstrated the traits of materials as potential anodes for designing high-performance asymmetric supercapacitors and also provided new insights for the development of high-performance materials for supercapacitors by using simple synthetic approach.