Precursor-based synthesis and electrochemical performance of LiMnPO4

Olivine-like LiMnPO4 was prepared from the NH4MnPO4 center dot H2O precursor precipitated from the aqueous solution. Different morphologies of the LiMnPO4 were obtained by the solid-state reaction of the precursor with LiOH (granular, 100-300 nm) and by ion-exchange reaction with eutectic mixture LiCl-LiNO3 (flake-like crystallites up to 10 mu m). The morphology and size distribution of the precursor NH4MnPO4 center dot H2O is preserved during ion-exchange, establishing a new preparation route for nanosized LiMnPO4. After ball-milling with carbon black the granular material delivers 30% of the theoretical capacity at C/5. The rate capabilities of the obtained materials are compared with the results from sol-gel synthesis in the light of particle size effect. (c) 2007 Elsevier B. V. All rights reserved.