Reduction Depth Dependent Structural Reversibility of Sn3(PO4)2

Conversion reaction is an important method for lithium storage. Tin-based compounds have been regarded as promising anode materials for lithium ion batteries due to their high specific capacities. Herein, we report the structural reversibility of Sn3(PO4)2 after conversion and Li–Sn alloying reactions. It is found that the reversibility of Sn3(PO4)2 is highly dependent on the cutoff discharge potential. The conversion reaction of Sn3(PO4)2 is partially reversible when it is discharged to 1.55 and then recharged to 3.00 V but is not between 0.00 and 3.00 V.