Bio-templated fabrication of three-dimensional network activated carbons derived from mycelium pellets for supercapacitor applications.

In this work, a three-dimensional porous mycelium-derived activated carbon (3D-MAC) was fabricated via a facile bio-templating method using mycelium pellets as both the carbon source and the bio-template. After ZnCl2 activation and high-temperature carbonization, the specific thread-like chain structure of mycelium in the pellets can be maintained effectively. The hyphae and junctions of the cross-linking hyphae form nanowires and carbon nanoparticles that link with the neighboring nanoparticles to form a network structure. By adding NH4 Cl, foreign nitrogen element doped (N-doped) 3D-MAC was obtained, which has a hierarchical porous structure composed of micropores and macropores. And the multiple pore size distribution benefits from ZnCl2 activation, the specific 3D structure and gas blowing. Meanwhile, the introduction of some hydrophilic groups and abundant N-containing functional groups in extrinsic N-doped 3D-MAC contributes to improving the Faradaic pseudocapacitance, respectively. A specific capacitance of 237.2 F g-1 at 10 mV s-1 was displayed, which is more than 1.5 times that of 3D-MAC. Even at the large scan rate of 500 mV s-1 , N-doped 3D-MAC still reveals a nearly symmetric rectangular shape, demonstrating great potential as a high-performance supercapacitor electrode material due to the synergistic effects of its 3D hierarchical porous structure and various functional groups.