Natural mushroom spores derived hard carbon plates for robust and low-potential sodium ion storage

Abstract

Biomass derived hard carbon has been considered a sustainable solution for sodium ion storage to improve the energy density of sodium ion batteries for low cost and large-scale energy storage. However, developing this kind of carbon materials with high specific capacity at low-potential platform is a critical issue. Herein, a new structure of hard carbon plate was developed via pyrolysis of mushroom spore (Ganoderma lucidum). The spore is mainly composed of chitin, distinguished from the lignin and cellulose in widely investigated biomass. The carbon plates obtained at 1400 °C have a suitable d002-spacing (0.371 nm) and ultra-low surface area down to 14.7 m2 g−1, resulting in a high reversible total discharge capacity of 305.8 mA h g−1 with an exceptional discharge capacity of 188.0 mA h g−1 at low-potential platform (0–0.1 V vs. Na+/Na) and excellent cycle stability as anode for SIBs. Meanwhile, the proportion of low-potential capacity in total capacity is 61.5%, which is significantly superior to previously reported carbon materials prepared using biomass from advanced plants. Furthermore, a full-cell constructed using the carbon plates as anode and sodium vanadate phosphate as cathode further validates the outstanding Na+ storage performance at low-potential, in which the battery delivers a high working voltage of 3.25 V, approaching the discharge potential of 3.3 V of sodium vanadate phosphate and a considerable energy density of 199.2 W h kg−1 (based on the total mass of cathode and anode). And it is also revealed that this high capacity for Na+ storage in the low potential range is attributed to the intercalation mechanism of NaC6 as the most possible intercalation compound. The hard carbon derived from natural spores in the work presents a new route to design low cost and efficient carbon materials as advanced anode for SIBs.