Fermentation-hot pressing assisted preparation of bamboo green-activated carbon for supercapacitors

The pre-treatment of biomass directly affects on the performance of its biochar. Biological fermentation is one of safe and effective pre-treatment approaches. To develop a novel high-performance biochar from bamboo residue for supercapacitor electrode materials, bamboo green residue was first pretreated with lactic acid bacteria fermentation-hot pressing, followed by carbonization-KOH activation to obtain bamboo-based activated carbon (B-ACs). The content of cellulose, lignin, and hemicellulose of fermented bamboo green residue changed and the microstructure was damaged. Then, the fermented bamboo residue was densified into block by hot pressing, which caused the decomposition of partial hemicellulose into furfural to form lignin-furfural bonds. The optimized the B-ACs from densified bamboo block had a more developed pore structure (specific surface area of 2634 m2 g−1, pore volume of 1.451 cm3 g−1) and thermal stability, and exhibited a high specific capacitance of 377.6 F g−1 at 0.5 A g−1 and high capacitance retention of 99.3 % after 2500 cycles with excellent electrochemical stability. Therefore, fermentation disassemble and hot pressing densification reconstruction proves to be a feasible strategy for enhancing the properties of bamboo-based biochar.