Morphology-controllable synthesis of LiCoPO4 and its influence on electrochemical performance for high-voltage lithium ion batteries

LiCoPO4 is a cathode material for 5V lithium ion batteries, but in practice it often suffers from the poor electrochemical performance due to its intrinsically slow ionic diffusion. Herein, various LiCoPO4 materials with different morphology, including unstructured nanoparticle, nanorod and microrod shape, have been synthesized by solvothermal methods and a subsequent annealing process in air. Electrochemical analysis shows that the controllable morphology has an influence in electronic and ionic pathways, thus affects the electrochemical performance. The nanorod shape LiCoPO4 shows the largest discharge capacity, the best rate capability and best cycling stability. Furthermore, the apparent Li+ ion diffusion coefficients of LiCoPO4 samples were determined to investigate the influence of particle shape and the orientation on the Li+ ions migration