Leveraging the Amorphous Nature of Sn–P Alloys for Improved Stability and Energy Density in Na‐Ion Batteries
Yixiang Zhang, Libin Zhang, Animesh Dutta, Ziwei Ye, Ben Tang, Michel Johnson, Nafiseh Zaker, Babak Shalchi‐Amirkhiz, Changlong Chen, J. R. Dahn, Chongyin YangABSTRACT
Developing alternative anode materials is a key route to improve the volumetric energy density of sodium‐ion batteries (SIBs). Here, Sn–P alloys with varying Sn/P atomic ratios are systematically evaluated as Na‐alloy anodes. Among them, SnP 3 outperforms all other alloys and offers the best balance between cost, volumetric capacity and cycling stability. SnP 3 can be made in either amorphous or crystalline forms. Crystalline SnP 3 becomes amorphous on sodiation and remains amorphous during cycling. Amorphous Na x SnP 3 shows a solid‐solution‐type and highly reversible sodiation/desodiation behavior, demonstrating exceptional cycling performance and structural stability. As comparison, the crystalline Sn 4 P 3 phase dealloys to Sn and a phosphorus containing phase upon repeated sodiation/desodiation, showing rapid capacity decay and severe particle pulverization. These findings highlight amorphous SnP 3 as a promising high‐energy‐density anode material for SIBs and provide valuable insights into how an amorphous structure influences Na‐alloy behavior.