High-yield microstructure-controlled amorphous carbon anode materials through a pre-oxidation strategy for sodium ion batteries

Abstract Owing to the low cost and abundant resource of sodium, sodium-ion batteries demonstrate bright application prospects for large-scale energy storage systems. Microstructure-controlled amorphous carbon with proper surface area and high electronic conductivity is considered to be one of the most promising anode material. Nevertheless, the cost of the reported carbon materials is still high because of the low carbon yield and expensive precursors. Besides, the low initial coulombic efficiency is also a big challenge. Herein, a high-yielding (70%) microstructure-controlled amorphous carbon is achieved via a pre-oxidation stabilization process and following carbonization of the mixed pitch and phenol formaldehyde resin precursor. The effects of pre-oxidation stabilization on adjusting the microstructure of amorphous carbon are systematically investigated, as well as the electrochemical performance. The optimal sample exhibits high initial coulombic efficiency (82%), high reversible capacity (268.3 mAh g−1 at 0.1 C) and good rate capability (106 mAh g−1 at 4 C) as an anode material of sodium-ion batteries. This high-performance amorphous carbon material is prepared via a controllable and low-cost strategy, presenting an appealing development of practical anode materials for sodium-ion batteries.