Insights into the microstructure evolution of starch-derived hard carbon for sodium-ion battery

Although starch-based hard carbons serve as the practical anodes for sodium-ion batteries, the formation mechanism of the microstructure influenced by the main components is still unclear. Here, the cassava starch with different amylose contents is employed to systematically establish the microstructure evolution mechanism of hard carbon and their effects on sodium storage performance. The results indicate that the regulation of starch components is crucial to achieving a short-range-ordered and a long-range-disordered structure with more active site during the pyrolysis process . The optimized 50SE-HC sample delivers a high reversible capacity of 316.83 mAh g −1 at 0.1C and stable cycling performances with 176.86 mAh g −1 after 1000 cycles at 4C. Deep insights into the microstructure evolution mechanism will greatly promote the rational design of starch-derived hard carbon anode with high performance. • Hard carbons (HCs) were developed using starch with different amylose contents. • The microstructure of HCs can be modulated by changing amylose contents. • The optimized 50SE-HC sample exhibits a record high Na + storage performance. • The work provides new insights for designing starch-derived hard carbon anode.