A green route to synthesize low-cost and high-performance hard carbon as promising sodium-ion battery anodes from sorghum stalk waste

摘要

Sodium-ion batteries（SIBs） have been considered to be potential candidates for next-generation low-cost energy storage systems due to the low-cost and abundance of Na resources. However, it is a big challenge to find suitable anode materials with low-cost and good performance for the application of SIBs. Hard carbon could be a promising anode material due to high capacity and expectable low-cost if originating from biomass. Herein, we report a hard carbon material derived from abundant and abandoned biomass of sorghum stalk through a simple carbonization method. The effects of carbonization temperature on microstructure and electrochemical performance are investigated. The hard carbon carbonized at 1300 ℃ delivers the best rate capability(172 mAh g-1 at 200 mA g-1) and good cycling performance(245 mAh g-1 after 50 cycles at 20 mA g-1,96% capacity retention). This contribution provides a green route for transforming sorghum stalk waste into ''''treasure''''of promising low-cost anode material for SIBs.