Synthesis and electrochemical characteristics of NASICON-structured LiSn2(PO4)3 anode material for lithium-ion batteries

Li3PO4, with a Li ion conductivity of 8.62 × 10−8 S cm−1, is considered as a matrix material in this study to improve the cyclability of tin anodes. Toward this goal, a well-crystallized NASICON-structured LiSn2(PO4)3 using nano-SnO2 as a precursor has been prepared at 900 °C using a solid-state reaction. Compared to SnO2, this material exhibits better cycling performance, with a capacity of 320 mAh g−1 after 50 cycles. Additionally, the insertion/extraction mechanism of LiSn2(PO4)3 is investigated through ex-situ X-ray diffraction (XRD) and electrochemical impedance spectroscopy (EIS) measurements. The apparent diffusion coefficient (DLi) is studied using cyclic voltammetry (CV) experiments employing a powder microelectrode. In addition, differential scanning calorimetry (DSC) measurements are employed to investigate the thermal stability of LiSn2(PO4)3.

► The NASICON-structured LiSn2(PO4)3 was prepared through a solid-state reaction. ► This material exhibits better cycling performance than SnO2. ► The lithiation mechanism was confirmed by ex-situ XRD and EIS tests. ► The improved cycling performance is due to the well formed Li3PO4 matrix.