Investigation of pyrolysed anthracite as an anode material for sodium ion batteries

Due to the increasingly serious problems of the greenhouse effect and environmental pollution caused by the continuous consumption of traditional fossil energy, renewable and clean energy (such as solar energy and wind energy) is facing new opportunities and challenges. However, renewable energy has intermittent and regional defects, and requires the assistance of large-scale energy storage systems, which put forward higher requirements for sustainable and low-cost energy storage technology. Due to the abundant reserves of sodium resources, sodium-ion batteries have been attracting more and more attention in recent years, and are considered as a beneficial supplement to lithium-ion batteries in the field of large-scale energy storage. However, there is still a lack of anode materials with excellent comprehensive properties to further improve the energy density of Na-ion batteries. Therefore, the industrialization of SIBs is of great significance to develop anode materials with excellent performance, low cost and easy availability. In this study, impurities were removed from anthracite coal by a combination of concentrated alkali high temperature pretreatment and concentrated acid treatment, followed by high temperature calcination to obtain hard carbon materials. The WYM affords an ultrahigh reversible capacity of 267.7 mA h g(-1) at 50 mA g(-1), a high rate performance of 158.4 mA h g(-1) at 5 A g(-1), and long-term cycling stability at 5 A g(-1) (similar to 83.3% retention after 2000 cycles). These excellent properties meet the requirements of practical applications and lay the foundation for the industrial production of low-cost, high-safety sodium-ion batteries for large-scale energy storage.