Pseudo bismuth vanadate anchored EDLC-MWCNTs: Supercapacitive electrode to a symmetric solid-state device

Sponge analogous nano pebbles of bismuth vanadate (BiVO₄) decorated over multi-walled carbon nanotubes (MWCNTs) synthesized by the successive ionic layer adsorption and reaction (SILAR) method have been explored towards supercapacitor application through enhanced (8 times) surface roughness (S_a) compared to bare MWCNTs; well supported by wettability studies. Electrochemical studies through CV, GCD, EIS, and electrochemical stability performances of the electrode have been performed in 1 M KCl electrolyte where MWCNTs/BiVO₄ showed the highest capacitance (1334.66 F/g) at 3 mV/s with good electrochemical stability of 103 % even after 3500 CV cycles. Interestingly, symmetric solid-state supercapacitor assembled using PVA embedded LiClO₄ gel exhibited a remarkable potential window of 1.83 V with corresponding energy and power densities of 18.38 Wh/kg and 2.13 kW/kg, respectively at 1 mA/cm². The novelty of this work lies in the introduction of a symmetric device using MWCNTs/BiVO₄ electrodes for the first time along with its potential for real-world use by illuminating ‘VNIT ‘acronym consisting of 21 red LEDs.