Programmable coating of polyaniline on hemispherical nitrogen-doped mesoporous hollow carbon as high performance material for supercapacitor

Miniaturized electronic and wearable devices require energy storage systems, which can store a large amount of energy in a very narrow space/volume. Supercapacitors are considered as promising devices for portable electronics due to their robust performance and ultra-high cycling stability; however, their volumetric capacitance is far from the reality. Herein, we have developed a hybrid of nitrogen-doped hemispherical structured carbon (HNC) and polyaniline (PANI). Synergistic contribution of pseudocapacitive PANI and electric double layer capacitive HNC results in remarkably improved electrochemical properties. An optimized HNC/PANI-0.05 composite displayed 16.19 times improvement in the volumetric capacitance (1263 F cm⁻³) and seven times in gravimetric capacitance (547 F g⁻¹) than that of pure HNC. The composite also showcases improved energy, power density, and cyclic stability. Hence, in the HNC/PANI-0.05 composite achievement of a balance between the mesoporosity and high value density imparts a high gravimetric capacitance together with an excellent volumetric capacitance.