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

• Anchoring of spongy bismuth vanadate nanopebbles over carbon nanotubes through well-controlled simple successive ionic layer adsorption and reaction (SILAR) method for the first time. • MWCNTs/BiVO 4 electrode exhibiting specific capacitance of 1334.66 F/g at 3 mV/s scan rate with remarkable electro chemical stability (capacitive retention) of 103 % even of 3500 CV cycles. • Designed symmetric MWCNTs/BiVO 4 solid-state supercapacitor device with PVA+LiClO 4 gel electrolyte exhibited potential window of 1.83 v with specific energy of 18.38 Wh/kg and power density of 2.13 kW/kg values at 1 mA/cm 2 . • Employing designed device to lighten ‘VNIT’ acronym panel consisting of 21 red LEDs to demonstrate practical application. Sponge analogous nano pebbles of bismuth vanadate (BiVO 4 ) 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/BiVO 4 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 LiClO 4 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/cm 2 . The novelty of this work lies in the introduction of a symmetric device using MWCNTs/BiVO 4 electrodes for the first time along with its potential for real-world use by illuminating ‘VNIT ‘acronym consisting of 21 red LEDs. MWCNTs/BiVO 4 electrode synthesis, Electrochemical testing and Flexible Solid-state symmetric supercapacitor device Practical demonstration