ZIF-67 Derived Co2VO4 Hollow Nanocubes for High Performance Asymmetric Supercapacitors

Abstract

In this work, a new type of Co2VO4 hollow nanocube (CoVO-HNC) was synthesized through an ion exchange process using ZIF-67 nanocubes as a template. The hollow nanocubic structure of the CoVO-HNC provides an abundance of redox sites and shortens the ion/electron diffusion path. As the electrode material of supercapacitors, the specific capacitance of CoVO-HNC is 427.64 F g−1 at 1.0 A g−1. Furthermore, an asymmetric supercapacitor (ASC) was assembled using CoVO-HNC and activated carbon (AC) as electrodes. The ASC device attains an energy density of 25.28 Wh kg−1 at a high-power density of 801.24 W kg−1, with 78% capacitance retention after 10,000 cycles at 10 A g−1.

Growth Dynamics‐Dependent Chemical Approach to Accomplish Nanostructured Cobalt Vanadium Oxide Thin Film Electrodes with Controlled Surface Area for High‐Performance Solid‐State Hybrid Supercapacitor Devices

“…Evidently, when the voltage scan rate increases, the area under the CV curve increases, although the redox pairs shift slightly in the CV loop owing to the polarization effect. [ 33,34 ]…”

“…Evidently, when the voltage scan rate increases, the area under the CV curve increases, although the redox pairs shift slightly in the CV loop owing to the polarization effect. [33,34] Furthermore, in a direction to evidently divulge the mechanism of charge storage of CVO series electrodes, their electrochemical kinetics are prodigious to study. [35] The scan rate (ν) versus peak current (i) in the CV area under the loop satisfied the "Power's law" as given below in Equation (R5) [36] i ¼ aν b (R5)…”

Vanadium Oxide-Based Electrode Materials for Advanced Supercapacitors: A Review

“…(c) Schematic diagram of the preparation, (d) SEM morphology and (e) specific capacitance of CoVO-HNC, (f) Ragone plots and (g) cycling performance of HSC. Reproduced with permission from ref . Copyright 2022 CC BY.…”

“…These results indicate that cobalt vanadate is very promising for the preparation of SC electrode materials. A new type of Co 2 VO 4 hollow nanocubes (CoVO-HNC) through an ion exchange process using ZIF-67 nanocubes as templates are synthesized by our group, and the preparation process is shown in Figure c . As shown in Figure d, the hollow nanocube structure of CoVO-HNC has a large specific surface area and a graded pore structure, which provide abundant redox sites and shorten ion/electron diffusion paths.…”

“…A new type of Co 2 VO 4 hollow nanocubes (CoVO-HNC) through an ion exchange process using ZIF-67 nanocubes as templates are synthesized by our group, and the preparation process is shown in Figure 8c. 131 As shown in Figure 8d, the hollow nanocube structure of CoVO-HNC has a large specific surface area and a graded pore structure, which provide abundant redox sites and shorten ion/electron diffusion paths. The synergistic interaction of cobalt and vanadium provides multiple redox pairs and also enhances the electrical conductivity.…”