Microwave solid-state synthesis and electrochemical properties of carbon-free Li3V2(PO4)3 as cathode materials for lithium batteries

Abstract: Monoclinic Li3V2(PO4)3 can be rapidly synthesized at 750°C for 5min (MW5m) by using microwave solid-state synthesis method. The refined cell parameters and atomic coordination of the sample MW5m show some deviations compared with those of the sample synthesized in conventional solid-state synthesis method, especially the coordinate of Li atoms. Compared with the electrochemical properties of the carbon-coating sample Li3V2(PO4)3, the carbon-free sample MW5m presents well electrochemical properties. In the cut-off voltage of 3.0–4.3V, MW5m sample presents a specific charge capacity of 132mAhg−1, almost equivalent to the reversible cycling of two lithium ions per Li3V2(PO4)3 formula unit (133mAhg−1), and specific discharge capacity of 126.4mAhg−1. In the cut-off voltage of 3.0–4.8V, MW5m shows an initial specific discharge capacity of 183.4mAhg−1 at 0.1C, near the theoretical discharge capacity. In the cycle performance, the capacity fade of Li3V2(PO4)3 is dependent on the cut-off voltage and the preparation method, more capacity lost at relatively higher charge/discharge voltage. The reasons for the excellent electrochemical properties of Li3V2(PO4)3 rapidly synthesized in microwave field are discussed in detail. [Copyright &y& Elsevier]