Biomass-derived carbon from Ganoderma lucidum spore as a promising anode material for rapid potassium-ion storage.

The design and preparation of powerful anode materials are key to developing potassium-ion batteries. A biomass-based potassium anode material with a distinct hollow-cage structure was prepared by one-step carbonization. The target carbon exhibited a specific surface area of 104.4 m2 g-1 and mesopores/macropores distributed materials. When used as the negative electrode of a potassium-ion battery, the cage-like porous carbon (CPC) showed a reversible capacity of 407 mAh g-1 after 50 cycles at 50 mA g-1 current density. After 100 cycles, at a current density of 200 mA g-1, the reversible capacity was 163.8 mAh g-1. It still exhibits an extremely long cycle stability at high current densities (discharge capacity of 124.6 mAh g-1 after 700 cycles at a current density of 1 A g-1). The excellent performance is attributed to the stable cage-like carbon scaffold and uniform continuous distribution of mesopores/macropores to improve ion diffusion kinetics and electronic conductivity. These results indicate that a properly designed CPC can effectively increase the capacity and cycle stability of a potassium-ion battery.