A Review of Pnictogenides for Next-Generation Anode Materials for Sodium-Ion Batteries

With the growing market of secondary batteries for electric vehicles (EVs) and grid-scale energy storage systems (ESS), driven by environmental challenges, the commercialization of sodium-ion batteries (SIBs) has emerged to address the high price of lithium resources used in lithium-ion batteries (LIBs). However, achieving competitive energy densities of SIBs to LIBs remains challenging due to the absence of high-capacity anodes in SIBs such as the group-14 elements, Si or Ge, which are highly abundant in LIBs. This review presents potential candidates in metal pnictogenides as promising anode materials for SIBs to overcome the energy density bottleneck. The sodium-ion storage mechanisms and electrochemical performance across various compositions and intrinsic physical and chemical properties of pnictogenide have been summarized. By correlating these properties, strategic frameworks for designing advanced anode materials for next-generation SIBs were suggested. The trade-off relation in pnictogenides between the high specific capacities and the failure mechanism due to large volume expansion has been considered in this paper to address the current issues. This review covers several emerging strategies focused on improving both high reversible capacity and cycle stability.