Size and shape controlled LiMnPO4 nanocrystals by a supercritical ethanol process and their electrochemical properties

In this paper, we report the preparation of systematically size and shape controlled LiMnPO4 nanocrystals under supercritical fluid conditions. The effect of different reaction conditions such as the reaction time, temperature, surfactant and precursor concentration on the size and shape of the LiMnPO4 nanocrystals was studied in detail. It was noticed that shorter reaction time and lower reaction temperature facilitated the formation of crystalline LiMnPO4 nanocrystals with size similar to 10 nm. The nanocrystals ranging from 7 to 24 nm were obtained by controlling different reaction conditions. The formation mechanism for the LiMnPO4 nanocrystals is proposed based on the obtained results. The effect of nanosize on the electrochemical properties of LiMnPO4 nanocrystals was studied. Improved electrochemical performance was observed for similar to 20 nm sized LiMnPO4 after conductive carbon coating. This study indicates the importance of LiMnPO4 nanocrystals below 50 nm size in improving the electrochemical performance of LiMnPO4 cathodes.