Application and prospective of Sn-P based anodes for alkali-ion batteries

Tin phosphide (Sn-P) based materials, comprising abundant elements on the earth, have attracted much attention as anodes for alkali-ion batteries. As one of the emerging families of tin phosphides, Sn4P3 is fast becoming a vital alternative anode for next-generation alkali-ion batteries mainly owing to its stable phase, appropriate operating potential, and high theoretical capacity. However, the fast capacity decay caused by the volume changes and Sn agglomeration greatly hinder its practical application. Thus, the tremendous effect has been made the address the above issues. Herein, we retrospect the development of Sn-P anode using Sn4P3 as an indicator and categorize the implemented methods to solve the problem of Sn4P3 in published work into four strategies, which are designing hierarchical/hollow nanostructures, constructing robust physical barriers of carbonaceous materials, doping or introducing heterophase interfaces, and modifying the solid-electrolyte interphase (SEI) layer. Besides, the application of the proposed strategies in other Sn-P based materials (e.g., SnP3 and SnP) in alkali-ion batteries were discussed. Finally, the remained challenges and perspectives for Sn-P based anodes of alkali-ion batteries were presented. This review systematically retrospect the progress of Sn-P materials, which not only will promote the development of Sn-P based anodes but also help to generate fresh insight into similar alloy-based materials.