Microwave Synthesis of Zinc Ammonium Phosphate/Reduced Graphene Oxide Hybrid Composite for High Energy Density Supercapacitors

Abstract

Herein, zinc ammonium phosphate (ZAP) is interluded with reduced graphene oxide (rGO) as a composite (ZAPG2) via microwave synthesis route. The ZAPG2 is investigated by X‐ray diffraction (XRD), Raman, scanning electron microscopy (SEM), X‐ray photoelectron spectroscopy (XPS), and electrochemical studies (cyclic voltammetry, galvanostatic charge discharge, and impedance). The Raman analysis confirms the graphitization of rGO in the ZAP, and XPS confirms the elemental composition. The SEM morphology reveals that rGO spreads over the micropyramidal envelope of ZAP. The ZAPG2//rGO device delivers a higher specific capacitance of 356 F g−1 for 5 m than in 3 m H2SO4 (133.7 F g−1) electrolyte at a current density of 1 A g−1 within the potential window of 1.8 V. The cyclic stability of 86.1% for 3 m and 66.6% for 5 m are noted for 5000 charge–discharge cycles. ZAPG2//rGO combination is the first attempt at facilitating better specific capacitances on device performance. This parallels in energy density, as 59.9 W h kg−1 in 3 m and 153.4 W h kg−1 in 5 m driving for the same power density of 448.3 W kg−1 at 1 A g−1, which suggests the hybrid composite device's practicality for high‐energy supercapacitor applications.

Role of dual redox additivesKI/VOSO4in manganese ammonium phosphate at graphene quantum dots for supercapattery

“…Figure 6A shows, in particular, the CV performances of pure MnAP, MnAP@GQD1, MnAP@GQD2, MnAP@GQD3, and MnAP@GQD4 at 5 mV s −1 . It is noticed that all hybrid electrodes show pseudocapacitive behavior with distinct redox peaks, 59 which is due to the adsorption and interaction of H + , and electrolyte ions with Mn 2+ states 33,46 . The anodic and cathodic peak potential differences and the corresponding increase in areas under the CV curve (Figure 6C) are in direct proportion with the scan rate revealing that the CV process is said to have quasi‐reversibility 60 …”

Graphene-guided growth of rare earth-doped Bi2Mo2O9 nano self-assembly for enhanced asymmetric supercapacitor device performance

“…There was higher specific capacitance at low current densities for the prepared electrodes, which is inconsistent with the ion exchange mechanism. 50–53 From the GCD graph, the specific capacitance can be evaluated by using the following equation:where the current density (A) is given by “ I ”, “Δ t ” represents the discharge time, “ m ” denotes the mass of the material (g) on the working electrode, and “Δ V ” is the applied voltage window (volts). 54…”

“…There was higher specic capacitance at low current densities for the prepared electrodes, which is inconsistent with the ion exchange mechanism. [50][51][52][53] From the GCD graph, the specic capacitance can be evaluated by using the following equation:…”

Single-wall and graphene-modified multiwall wasp nest shaped Bi2Mo2O9 self-assembly for performance-enhanced asymmetric supercapacitor

“…Based on the findings of the GCD and CV tests, the M-Bi 2 Mo 2 O 9 electrode may be suggested as a promising electrode material. 39,54–57…”