MnO2-doped, polyaniline-grafted rice husk ash nanocomposites and their electrochemical capacitor applications

The utilization of renewable rice husk ash (RHA) in an energy storage system without any activation is described. Polyaniline-grafted RHA (PANI/RHA) and MnO2-doped, polyaniline-grafted RHA (PANI/MnO2/RHA) nanocomposites were developed. The capacitance behaviour of the developed nanocomposites was well studied using cyclic voltammetry and charge-discharge methods. The results of galvanostatic charging and discharging show a 17-fold improvement in capacitance behaviour of PANI/RHA and a 54-fold enhanced capacitance of PANI/MnO2/RHA nanocomposites compared to that of neat RHA. The enhanced capacitance and rate capability of RHA are attributed to the synergistic effect of polyaniline with RHA and also the high utilization of pseudo-active species for ion/electron transfer.