Attaining superior performance in an aqueous hybrid supercapacitor based on N-Doped highly porous carbon spheres and N-S dual doped Co3O4

Cobalt oxide (Co 3 O 4 ) has seen a significant interest for its application as an electrode for supercapacitors, due to its cost-effectiveness, high theoretical capacitance and outstanding redox activity. However, Co 3 O 4 exhibits poor electrical conductivity and cycle life restricting its high-power energy storage applications. High porosity carbons are materials of choice for applications in electric double layer charge storage but suffer from poor energy densities due to limited charge storage capabilities. Here we propose a hierarchical functionalization strategy to develop N, S co-doped Co 3 O 4 and N doped high porosity carbon micro-spheres for efficient and durable hybrid supercapacitor. Benefiting from the structural eminence, improved electrical conductivity and high quantity of N content, the heteroatom enriched N, S co-doped Co 3 O 4 and N doped porous carbon spheres demonstrates superior electrochemical performance. Moreover, hybrid supercapacitor cell with N, S co-doped Co 3 O 4 as a cathode and N doped porous carbon spheres as anode deliver a high specific energy of 52 Wh kg -1 at power density of 1462 W kg -1 coupled with the capacity retention of 95 % after 5,000 charge-discharge cycles. Therefore, by improving both anode and cathode simultaneously can be considered an effective approach to enhance energy storage capabilities of hybrid supercapacitors while maintain exceptionally high-power densities.