K2CO3 regulation of Hericium erinaceus–derived porous carbon for high-performance supercapacitors

Biomass-derived carbon materials have attracted extensive attention for supercapacitor electrodes due to their sustainability and low cost. Notably, Hericium erinaceus , a natural biomass with a unique three-dimensional porous structure and high protein/polysaccharides content, has rarely been explored as a carbon precursor for supercapacitor electrodes. Herein, Hericium erinaceus is employed as a novel carbon precursor, and K 2 CO 3 is used as an activator to prepare oxygen/nitrogen self-doped hierarchical porous carbon via a low-temperature carbonization-high-temperature activation strategy. Benefiting from the moderate etching effect of K 2 CO 3 , the as-prepared carbon material possesses a well-developed micro-mesoporous hierarchical structure, which facilitates ion diffusion and electron transfer. Electrochemical tests demonstrate that the optimal sample (HEPC-3) delivers a specific capacitance of 300 F g −1 at a scan rate of 0.5 A g −1 , along with excellent rate capability. Furthermore, the HEPC-3//HEPC-3 symmetric supercapacitor achieves an energy density of 14.5 Wh kg −1 at a power density of 57.9 W kg −1 , and maintains a specific capacitance retention rate of 107% after 10,000 cycles at 100 mV s −1 . This work systematically clarifies the structure-performance relationship regulated by K 2 CO 3 activation, providing a new strategy for the design of high-performance biomass-derived carbon electrodes for supercapacitors.