Synthesis of high tap density Li3V2(PO4)3 cathode materials using mixed lithium precursors

High tap density Li3V2(PO4)3 cathode materials were synthesized using mixed LiF and LiNO3 as lithium precursors, LiNO3 was used as the sintering agent. Rietveld refinement results show that no impurities phases are detected in products. Particle size distribution and tap density measurement results show that particle size and tap density of products can be increased by the addition of LiNO3. Electrochemical characterization results show that electrochemical performance of products is declined with the increase in contents of LiNO3 in the lithium precursors. Only a small amount of LiNO3 added in the lithium precursors (mole ratio of LiNO3 to LiF is 1:9) can increase the tap density and also retain the good performance of products. Scanning electron microscopy (SEM) images indicate that the samples prepared by mixed lithium precursors present particles agglomerate, and the particle size increased with increase in contents of LiNO3. Large amount of LiNO3 added in the lithium precursors induces the particles to become spheric and smooth, which worsens the performance. The particles obtained with the mole ratio of LiNO3 to LiF in 1:9 show a flake-like shape with a high specific surface area, which leads to good electrochemical performance.