Research and application progress of electrolyte solution for hard carbon anodes in sodium-ion batteries

along with excellent cycling and rate performance, making it the core anode material for the commercialization of SIBs. Moreover, by acting as an ion transport channel and participating in the construction of the electrolyte solution/hard carbon interface, the electrolyte formulation directly affects the performance of the hard carbon anode. This paper reviews the research progress of electrolyte solution for hard carbon (HC) anodes in SIBs and systematically compares five categories of electrolyte solution systems, namely classic carbonate ester electrolyte solution, ether-based electrolyte solution, high-concentration electrolyte solution, phosphate-based electrolyte solution, and new-type electrolyte solution such as carboxylate, sulfone, and nitrile-based electrolyte solutions. Meanwhile, it sorts out the characteristics and optimization paths of the aforementioned electrolyte solutions, which is of great significance for breaking through interface bottlenecks and promoting the development of SIBs.