Recent Progress of Hard Carbon Anode Materials for Sodium Ion Batteries

Sodium ion batteries (SIBs) have been regarded as the compatible and complementary to lithium ion batteries for energy storage due to abundant sodium resources, low cost and excellent low temperature performance. Therefore, accelerating the commercialization of SIBs can reduce the risk of lithium supply to ensure the long-term stable development of the new energy industry. As the host material for intercalation of large-radius sodium ions, the related design and development requirements of anode material are more demanding. Currently,hard carbon (HC) has been considered one of the most suitable anode materials for sodium ion batteries and large-scale commercialization. This paper reviews the bottleneck of high performance SIBs development, the materials characteristics,sodium storage mechanism and functionalized design strategies of hard carbon materials. Moreover,the advantages and disadvantages of various optimization strategies are discussed. Finally, future developments and challenges relating to ideal HCs are also proposed on the basis of recent progress.