Growth Dynamics‐Dependent Chemical Approach to Accomplish Nanostructured Cobalt Vanadium Oxide Thin Film Electrodes with Controlled Surface Area for High‐Performance Solid‐State Hybrid Supercapacitor Devices

Rational designing of electrode materials having high surface area can accomplish the enhanced charge‐storing ability of the electrochemical energy storage devices. Therefore, the surface area of cobalt vanadium oxide (CVO) material is controlled by changing growth dynamics in successive ionic layer adsorption and reaction methods. Structural analysis confirms the formation of hydrous cobalt vanadium oxide nanoparticles (Co3V2O8⋅nH2O) thin film electrodes, and alteration in the surface area with change in growth dynamics is observed in Brunauer–Emmett–Teller analysis. The CVO1:1 thin film electrode prepared at optimal growth dynamics illustrates high specific capacitance (Cs) (capacity) of 793 F g−1(396.7 C g−1) at 0.5 A g−1, respectively. Moreover, aqueous hybrid supercapacitor devices constructed using CVO1:1 as cathode exhibit high Csof 133.5 F g−1at 1.1 A g−1, specific energy (SE) of 47.7 Wh kg−1with specific power (SP) of 0.90 kW kg−1. The solid‐state hybrid supercapacitor devices also offer high Csof 102.9 F g−1at 0.3 A g−1, SE of 36.6 Wh kg−1at SP of 0.30 kW kg−1. In the SILAR approach, the dipping time plays a critical role in improving the surface area of the material and, consequently, electrochemical performance, as the current work amply indicates. The surface area of cobalt vanadium oxide (CVO) material is controlled by changing growth dynamics through dipping time variation in successive ionic layer adsorption and reaction method, and fabricated hybrid supercapacitor devices comprised with optimized CVO1:1 cathode demonstrate high electrochemical performance.