High-performance, nano-structured LiMnPO4 synthesized via a polyol method

A novel polyol synthesis was adopted to synthesize nano-structured LiMnPO4. This route yields well-crystallized nanoparticles with platelet morphology that are only similar to 30 nm thick oriented in the b direction. The obtained material presented a good rate behavior and a very long cyclic life both at room temperature (RT) and 50 degrees C. The sample exhibited a specific capacity of 145 mAh g(-1) at C/20, 141 mAh g(-1) at C/10 rate and 113 mAh g(-1) 1C rate. This represents is the highest performance results reported to date for this material. The high rate performance is ascribed to the platelet shape of the LiMnPO4 as it minimizes the paths for Li diffusion. At elevated temperature (50 degrees C) this material demonstrated improved reversible capacity of 159 mAh g(-1) at C/10 and 138 at 1C. The electrode retained 95% of its capacity, over 200 cycles, both at RT and 50 degrees C. This electrochemical stability is ascribed to the structural strength of the P-O bond and the stability of the electrolyte-LiMnPO4 interface. It allows us to conclude that the impact of a possible Jahn-Teller distortion is not critical. These excellent results clarified some ambiguities on LiMnPO4 as cathode materials. and demonstrate its promise for its practical application. (C) 2008 Elsevier B.V. All rights reserved.