High performance LiMnPO4/C prepared by a crystallite size control method

A carbon matrix, for restricting growth of LiMnPO4 crystallites, is built on the small Li3PO4 crystallites precipitated from aqueous solutions, by the pyrolysis of sucrose. LiMnPO4 is prepared using the carbon coated Li3PO4 as one of the reactants (the other reactant is MnSO4) and the nuclei by a solvothermal method. Smaller-crystallite-size (8–12 nm) LiMnPO4 is successfully obtained on the carbon matrix by a crystallite size control method. The as-prepared LiMnPO4/C sample presents the desired electrochemical performance, including higher discharge potential plateau, larger discharge capacity, excellent high-rate capability, and good cycle stability. It is also confirmed that the smaller LiMnPO4 crystallites on the carbon matrix are beneficial for shortening the lithium ion diffusion path and increasing the electrical conductivity of the LiMnPO4/C sample, contributing to an improvement in electrochemical performance. The methodology described in this work could be helpful in the development of LiMnPO4/C cathode materials for lithium ion batteries with high energy density.