Enhanced electrochemical performance of in situ polymerized V2O5-PANI nanocomposites and its practical application confirmation by assembling ionic liquid as well as solid state-based supercapacitor device

Abstract

In the present study, in situ polymerization of anilinium hydrochloride over V2O5 was used to prepare PANI nanocomposites with varying weight percentage of V2O5 (10, 20 and 30 wt%). V2O5 nanoparticles were synthesized using a simple chemical approach and their purity was confirmed through Rietveld refinement. It confirmed the advantageous electrochemical activity of V2O5 with a higher oxidation state of vanadium (V+5), enabling efficient electron storage. For fabricated electrode materials, the pair of redox peaks as well as their shape in CV suggests the faradic pseudocapacitive properties. Among all prepared electrodes, 20 wt% V2O5-PANI (PV2) nanocomposite demonstrates maximum specific capacitance of 820.5 Fg−1 at a current density of 1 Ag−1 with decent capacitive retention of 88 % after 1000 charge–discharge cycles. PV2 electrode also has a lower charge transfer resistance (Rct) of 0.5 Ω and lesser solution resistance (Ro) of 0.31 Ω in 6 M KOH electrolyte which is also responsible for good electrochemical performance. The higher capacitance value and decent stability of PV2 confirmed its ordered structure with more active sites shown through FESEM, which significantly contributes to efficient ion and electron transfer. In addition, the symmetric supercapacitor configuration of PV2 electrodes exhibits good energy and power densities of 4.6 Wh kg−1 and 80.7 W kg−1, respectively. Finally, the ignition of a red LED using three PV2//PV2 symmetric devices connected in series underscores its potential to advance energy storage applications.

Keywords

• Polyaniline
• V2O5
• V2O5-PANI nanocomposites
• Rietveld refinement
• Electron density maps
• Specific capacitance and Supercapacitor device