Electrochemical Performance of LiMnPO[sub 4] Synthesized with Off-Stoichiometry

was synthesized from an off-stoichiometric mix of starting materials with nominal composition . Stoichiometric with particle size was found with X-ray diffraction even with the large overall deviation from stoichiometry in the sample, indicating that other noncrystalline compounds are present. The off-stoichiometric sample had a discharge capacity of 145 mAh/g at C/10 and at 2C after a constant current constant voltage charge. Capacity retention was excellent without a significant capacity loss at 1C. The performance of could not be significantly improved by diluting the electrode with more carbon, indicating a more intrinsic kinetic limitation of the material for in contrast to [ Nature (London) , 458 , 190 (2009) ]. This is further corroborated by the difference in the overpotential between the two materials. Although has a sloping voltage profile, tends to have a constant overpotential at high rate.