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

Abstract 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 ( $${C}_{SP}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>C</mml:mi> <mml:mrow> <mml:mi>SP</mml:mi> </mml:mrow> </mml:msub> </mml:math> ) 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 $$(Qs)$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mo>(</mml:mo> <mml:mi>Q</mml:mi> <mml:mi>s</mml:mi> <mml:mo>)</mml:mo> </mml:mrow> </mml:math> 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.