| The monoclinic Li3V2(PO4)3 has good high-rate discharge performance, outstanding low temperature performance, excellent stability structure. In this paper, Li3V2(PO4)3 cathode material was successfully synthesized by a carbothermal reduction method using water as ball mill dispersant, and it was mixed with LiFePO4 to form xLi3V2(PO4)3·yLiFePO4.The recovery of active materials from spent lithium-ion electrodes was studied. Its structure and morphology were investigated using XRD, SEM, TEM and XPS, electrochemical methods of CV, EIS and charge-discharge testing were investigated the electrochemical performance of the materials.Firstly, consider the effect of different solid-liquid ratio (g·mL-1) using water as ball mill dispersant on performances of Li3V2(PO4)3. The result show that when the solid-liquid ratio is 3:10, the Li3V2(PO4)3 material has better electrochemical performance, the first discharge capacity of the Li3V2(PO4)3 material are 119.6 mAh·g-1(1C)and 106.4 mAh·g-1(10C), and the capacity retention are 96.3%(1C) and 98.4%(10C) after 100 cycles, respectively. Meanwhile, The differences in the electrochemical performance of Li3V2(PO4)3 material synthesized with ethanol and water mixture as ball mill dispersant was compared. At Vethanol:Vwater=1:0, the first discharge capacity of the Li3V2(PO4)3 material is highest, reaching 122.5 mAh·g-1 (1C), and the capacity retention is 97.3% after 100 cycles.Secondly, the performances of xLi3V2(PO4)3·yLiFePO4 mixed materials was investigated. The result show that The electrochemical performances of Li3V2(PO4)3·LiFePO4 obtained from direct mixed Li3V2(PO4)3 and LiFePO4 are better than that of Li3V2(PO4)3·LiFePO4 obtained from milling mixed Li3V2(PO4)3 and LiFePO4, the maximum discharge capacity of Li3V2(PO4)3·LiFePO4 obtained direct mixed Li3V2(PO4)3 and LiFePO4 is 135.7 mAh·g-1(1C), and the capacity retention is 96.3% after 100 cycles. The research of different proportions Li3V2(PO4)3 and LiFePO4 showed the maximum discharge capacity of Li3V2(PO4)3·LiFePO4 is 92 mAh·g-1(10C), which is better than the LiFePO4.Finally, the recovery of active materials from spent Li3V2(PO4)3 electrodes was studied. The active materials of spent Li3V2(PO4)3 electrodes was obtained from leaching by NaOH, and then the precursor was obtained using dissolution method by HCl, Li3V2(PO4)3 was re-synthesized, ultimately. The result show that the re-synthesized Li3V2(PO4)3 has good crystalline, less impurities, and excellent electrochemical performance. The first discharge capacity of the re-synthesized Li3V2(PO4)3 is 93.8 mAh·g-1(1C), and the capacity retention is 98.4% after 50 cycles. |
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