Investigations of redox-active polyoxomolybdate embedded polyaniline-based electrode material for energy application

Higher capacitance supercapacitors have received considerable attention, including their massive power density, high stability, and long cycle life. On the other hand, polymers have been known for their energy storage device application because of the pseudocapacitance behavior resulting from the extended conjugation over the polymer backbone. Here, we report a simple chemical bath deposition method for the synthesis of two polyoxometalates (H₄[PVMo₁₁O₄₀] and H₅[PV₂Mo₁₀O₄₀]) impregnated polyaniline (PAni) composite (PVMo₁₁@PAni and PV₂Mo₁₀@PAni) for electrochemical supercapacitors. Various analytical methods characterized the electrode materials, e.g., Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), powder X-ray diffraction (PXRD) method, and the morphological features of those electrodes were acquired by field emission scanning microscopy (FESEM). The exceptionally high average capacitance of 1371 F g⁻¹ was obtained for the composite PVMo₁₁@PAni electrode at a 3 A g⁻¹ current density and 1 V potential window with an energy density of 137.5 W h kg⁻¹. The PVMo₁₁@PAni composite electrode showed almost 4.3 times the higher energy density than pure PAni and 2.3 times higher than PV₂Mo₁₀@PAni. In contrast, PV₂Mo₁₀@PAni composite showed 1.9 times more energy density than pure PAni composite electrode. Interestingly, high average capacitance, charge–discharge rates, and high energy density with high-level power delivery make them promising electrode candidates for supercapacitors.