Oxygen-enriched hierarchical porous carbon supported Co-Ni nanoparticles for promising hybrid supercapacitors via one step pyrolysis of polymerized high internal phase emulsion

•A one-step pyrolysis strategy was introduced to immobilize Co-Ni nanoparticles on oxygen-enriched hierarchical porous carbon.•This energy-saving strategy is achieved through high internal phase emulsion templating assisted by facile self-crosslinking.•The optimized Co-Ni/OHPC electrode exhibited the highest specific capacitance of 817.3 F g−1 at 5 mV s−1.•The assembled hybrid supercapacitor possessed an appreciable energy density of 66.94 Wh kg−1 at 409.9 W kg−1. [Display omitted] The urgent demand for high-performance energy storage components has been driving the exploration for superior battery-type electrode materials for hybrid supercapacitors, which is challenging but of considerable significance. In this paper, a one-step pyrolysis route was elaborated to prepare oxygen-enriched hierarchical porous carbon supported Co-Ni nanoparticles Co-Ni/OHPCs) by facile self-crosslinking assisted high internal phase emulsion (HIPE) templating. The oxygen-enriched porous carbon framework provides large specific surface area and structural stability, meanwhile Co doping can significantly reinforce the electrochemical performance of the Co-Ni/OHPCs battery-type electrodes. By optimizing the ratio of Ni2+ to Co2+ ions, the obtained Co-Ni/OHPC electrodes exhibited excellent electrochemical performance of 817.3 F g−1 at a scan rate of 5 mV s−1. Furthermore, coupling with an activated porous carbon anode, the assembled hybrid supercapacitor (HSC) possessed an appreciable energy density of 66.94 Wh kg−1 at 409.9 W kg−1 and a capacitance retention ratio of 73.89% after 5000 cycles, showing considerable application prospects. This structural design strategy provides new inspiration for the reasonable optimization of new electrode materials for promising hybrid supercapacitors.