Research progress in preparation technology of pitch-based carbon anode materials for sodium-ion batteries
Recently,sodium-ion batteries(SIBs)have been considered as a promising candidate as a new energy storage technology in the field of energy storage owing to their high safety and low cost of sodium.Carbon anodes act as a vital role in the components of SIBs.However,the related material preparation,sodium storage mechanism research and comprehensive performance improvement are still quite challenging now.Pitch-based precursors own the advantages of low cost,high carbon content and high carbon yield,and they have been considered as potential carbon sources for the synthesis of carbon anodes in SIBs.However,direct high-temperature pyrolysis and carbonization of pitch-based carbon sources will produce highly graphitized carbon with small carbon layer spacing,resulting in relatively low sodium storage capacity.This results an unsatisfied sodium storage capacity.In recent years,many attempts have been made to solve the difficult problems of graphitization and rearrangement for pitch-based carbon sources during the carbonization process.Various strategies have been proposed,such as asphalt modification,structural design,surface modification and carbon recombination.Owing to these efforts,the sodium storage performances of the obtained carbon anodes have been significantly improved.This review summarizes the current technological progress for the preparation of carbon anodes by using pitch as carbon source in detail.We further discuss the crucial problems and possible research priorities of pitch derived carbon anodes for SIBs in future.This review may provide a deep insight into the development of low-cost and high-performance pitch-based carbon anode for SIBs and realize the high-value utilization of pitch-based precursors.