Abstract: The invention describes a method for making nano-sized crystalline LiMnPO4 powder with controlled morphology by direct precipitation at low temperature. It also describes a method for making a carbon coated LiMnPO4 composite powder with enhanced electrochemical performances. The manufacturing process comprises the steps of:—providing a water-based mixture having at a pH between 6 and 10, containing a dipolar aprotic additive, and Li(I), Mn(II) and P(v) as precursor components;—heating said water-based mixture to a temperature between 60° C. and its boiling point, thereby precipitating crystalline LiMnPO4 powder. The above process yields a powder for use as cathode material in Li batteries with high reversible capacity and good rate properties.