Superior high rate capability of tin phosphide used as high capacity anode for aqueous primary batteries

Tin phosphide (Sn4P3) with a layered structure was synthesized by direct ball-milling method and tested for possible use as an electroactive anode material in alkaline aqueous solution. The experimental results demonstrated that the Sn4P3 electrode could deliver a discharge capacity of 775 mAh/g at the constant current of 200 mA/g, 716 mAh/g at 2000 mA/g and 511 mAh/g at 5000 mA/g respectively, showing a superiorly high rate capability in alkaline aqueous solution. The excellent electrochemical activity of the Sn4P3 material is found to arise from the cooperative interaction of the P and Sn atoms in the layered crystalline structure, in which the Sn atom layers serve as a conductive framework providing an electronic passage for the 5-electron oxidation of the P atoms.