Research progress of carbon materials in the anodes of sodium-ion batteries

Sodium-ion batteries (SIBs) have attracted the attention of sustainable energy due to their low cost and availability of sodium. A variety of carbon anode materials such as graphite, hard carbon, soft carbon, and graphene are widely used in sib because of their diversity of structure and chemical properties. These materials store sodium ions differently, and graphite needs to be modified for better performance. Hard and soft carbon provide high capacity but have problems with electrical conductivity and expansion. Carbon nanostructures, including graphene, have many active sites but are expensive to produce. To improve the properties of carbon materials, strategies such as increasing layer spacing, controlling porosity, and introducing defects are discussed. Understanding the structure of the substance and the mechanism of sodium storage is crucial. The future of sib carbon anodes includes the pursuit of green, low-cost materials, and synthesis methods, as well as the use of advanced technologies for material optimization.