Enhanced electrochemical performance of hybrid α-MnO2/PANI nanocomposites for energy storage devices

alpha-MnO2 and in-situ synthesized alpha-MnO2/PANI nanocomposites with varying alpha-MnO2 concentrations (5 %, 10 %, 20 %, 30 %, 40 %, and 50 %) were developed for energy storage applications. PXRD analysis confirmed that the alpha-MnO2 nanoparticles crystallized in an orthorhombic structure with the I4/m space group. FESEM and TEM analyses revealed the formation of a network-like structure in the alpha-MnO2/PANI composites, exhibiting stronger cohesion compared to bare alpha-MnO2. These structural improvements enhanced the surface-to-volume ratio and interfacial binding, enabling efficient electrochemical reactions and improved charge storage capabilities. Among the compositions, the 20 % alpha-MnO2/PANI nanocomposite demonstrated superior DC conductivity (1.84 x 10-3 S cm- 1) and enhanced H+ ion diffusion compared to the other samples. Electrochemical evaluations performed in a 1 M HCl electrolyte using cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) techniques identified the 20 % alpha-MnO2/PANI composite as the most effective electrode material. It achieved a remarkable specific capacitance of 696.66 F g- 1 at a current density of 1 A g- 1 and exhibited excellent cyclic stability over extended redox cycles. These results underscore the significantly enhanced energy storage performance of the 20 % alpha-MnO2/PANI nanocomposite compared to pure alpha-MnO2, establishing it as a promising candidate for high-performance supercapacitor electrode applications.