SYNTHESIS AND ELECTROCHEMICAL BEHAVIOUR OF TIN PHOSPHATE AS ANODE MATERIAL FOR LITHIUM ION CELLS

Abstract

This study aims to explore the possibility of tin phosphate application as anode material in lithium ion cells. Two batches of tin phosphates have been synthesized via a chemical route where one batch was synthesized with the sodium dodecyl sulfate surfactant to produce mesostructured tin phosphate and the other was synthesized without the surfactant. From X-ray diffraction (XRD) analysis, the synthesized tin phosphate which was calcined at 500°C showed crystalline characteristics whereas that of mesostructured tin phosphate maintained an amorphous nature. Electrochemical measurements showed reversible lithium ion reaction upon charging and discharging of the tin phosphate anodes within the potential range of 0 – 2V versus Li+/Li. Upon the first cycle, tin phosphate delivered a reversible capacity of 272 mAh/g whereas mesostructured tin phosphate delivered that of 590mAh/g. Substantial capacity losses and fading upon further cycling was experienced by both anodes due to the formation of irreversible phase and restriction in the reversible lithium-tin formation. It is believed that mesostructured tin phosphate anode exhibited better capacity retention because of its porous structure which minimized the effect of volume changes experienced by the anode during the charge-discharge cycling process.