Original electrochemical mechanisms of CaSnO3 and CaSnSiO5 as anode materials for Li-ion batteries

Calcium stannate (CaSnO3) and malayaite (CaSnSiO5) were synthesized by means of a high temperature solid-state reaction. Their crystal structures and morphologies were characterized by X-ray diffraction (XRD) and Scanning Electron Microscopy; their electrochemical properties were analyzed by galvanostatic tests. The amorphization of the initial electrode materials was followed by XRD. The first discharge of the oxides CaSnO3 and CaSnSiO5 shows a plateau at low potential, which is due to the progressive formation of Li–Ca–Sn and/or Li–Sn alloys as shown by 119Sn Mössbauer spectroscopy. The results reveal similar electrochemical mechanisms for CaSnO3 and CaSnSiO5 but they completely differ from those related to SnO2.