Large-scale synthesis of ternary Sn5SbP3/C composite by ball milling for superior stable sodium-ion battery anode

Abstract

Alloy-based materials (i.e. Sn, Sb, P) are promising candidates for sodium-ion battery (SIB) anodes, but they suffer from capacity decay during charge/discharge cycling due to the pulverization caused by their huge volume change. Nanostructures can slow down the capacity fade, but most of the synthesis methods of such nanostructured anodes are difficult to scale-up. Herein, a ternary Sn5SbP3/C composite was fabricated by a green, low cost, one-step and easily scalable ball-milling of elementary Sn, Sb, P, and C. The microstructure of the ball-milled powders consists of micrometric agglomerates of active nano Sn4P3 and SnSb and Sn particles. Carbon in the composite acts as a conducting matrix, and it does not only benefit to the ball milling efficiency, but also benefit to the cycle life of the electrode. Each of the active Sn4P3 and SnSb and Sn phases in the composite functions mutually as a buffer for the others. As a result, this ternary composite anode delivers a good capacity of 352 mA h g−1 at the current density of 2 A g−1, which is notably higher than that of the binary Sn4P3/C and SnSb/C composites produced under the same conditions.