Biomass-derived carbon materials have been widely researched due to their advantages such as low cost, environmental friendliness, readily available raw materials. Black fungus and Hericium erinaceus contain many kinds of amino acids. In this paper, unique O, N-codoped black fungus-derived activated carbons (FAC _X ), and Hericium erinaceus-derived activated carbons (HAC _X ) were prepared by KOH chemical activation under different temperatures without adding additional reagents containing nitrogen and oxygen functional groups, respectively. As electrode materials of symmetric supercapacitors, FAC₂ and HAC₂ calcined at 800 °C exhibited the highest specific capacitance of 209.3 F g^-1 and 238.6 F g^-1 at 1.0 A g^-1 in the two-electrode configuration with 6.0 M KOH as the electrolyte, respectively. The X-ray photoelectron spectroscopy confirmed that the as-synthesized FAC _X and HAC _X contained small amounts of nitrogen and oxygen elements. Moreover, heteroatom-doped FAC₂ and HAC₂ electrode materials shown excellent rate performance (84.1% and 75.0% capacitance retention at 20 A g^-1, respectively). By comparison, the oxygen-rich hierarchical porous carbon (HAC₂) shows higher specific capacitance and energy density and longer cycling performance. Nevertheless, carbon-rich hierarchical porous carbon (FAC₂) indicates excellent rate performance. Biomass-derived heteroatom self-doped porous carbons are expected to become ideal active materials for high performance supercapacitor.

Quanyuan Mao

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