Nanostructured bismuth phosphate-based asymmetric supercapacitor: electrochemical evaluation and oscillator application

Phosphate-based materials have received significant attention for various applications. In supercapacitors, metal phosphates exhibit high capacitance and superior rate performance. In this work, a wet chemical route was applied for the fabrication of aniline stabilized monoclinic bismuth phosphate (BPO) particles within the size range of 4-10 nm. The synthesized material was utilized as an active component for the application of a supercapacitor. The performances of the material were examined on a nickel foam for a three-electrode electrochemical cell. The material showed the maximum specific capacitance (CSP\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${C}_{SP}$$\end{document}) value of 255 F.g-1 at the current density (CD) of 2 A.g-1. Further, an asymmetric supercapacitor (ASC) device was fabricated with BPO and single wall carbon nanotube (SWCNT) as negative and positive electrodes, respectively, which delivered a specific capacity (Qs)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$(Qs)$$\end{document} value of 1462 mAh.g-1 under the CD of 0.4 A.g-1 with the energy density (ED) and power density (PD) values of 2.2 Wh.kg-1 and 0.68 kW.kg-1, respectively. The device exhibited capacity retention and coulombic efficiency (CE) values of 84 and 95% at 0.9 A.g-1 for 10,000 galvanostatic charge-discharge (GCD) cycles. The ASC device generated a low-frequency waveform and has the potential to function as an oscillator.