Hard-soft carbon nanocomposite prepared by pyrolyzing biomass and coal waste as sodium-ion batteries anode material

Sodium-ion batteries (SIBs) is a promising candidate to lithium-ion batteries (LIBs) due to inexhaustible sodium resources, cost effectiveness, and similar operation mechanism to LIBs. Currently, it is critical to develop high capacity, high cycling stability, and high rate-performance anode materials. Herein, a hard-soft carbon (HC-SC) nanocomposite is prepared by pyrolyzing a mixture of biomass and coal waste and usd as SIBs' anode material. The HC shows a porous structure with many open pores which are partly filled with the SC. Such structure of HC-SC composite can reduce the solid electrolyte interface formation. As a result, HC-SC composite displays an initial capacity of 261 mAh g−1 with a high initial coulombic efficiency of 92.3 % and remains a stable capacity of 241 mAh g−1 after 100 cycles at 50 mA g−1, which is higher than that of bare HC.