Synthesis of Nanometric LiMnPO4 via a Two-Step Technique

A two-step procedure for preparation of LiMnPO4 with small particle size (15-20 nm) and embedded in a carbon matrix is presented. The crucial point that prevents excessive particle growth is the avoidance of lithium in the first firing step, so that small Mn2P2O7 particles embedded in carbon are obtained. Because of the carbon matrix, the Mn2P2O7 particles also cannot grow in the second step, which involves lithiation and heating to 700 degrees C in argon. The prepared LiMnPO4 shows a high theoretical capacity (up to 95% of the theoretical value) and a stable cycling (>130 mAh/g, even after 100 cycles at 55 degrees C and a rate of C/20). At room temperature and using the CC-CV mode, the performance is comparable to the best result shown in the literature so far. Finally, the performance of LiMnPO4 is briefly compared with that of LiFePO4.