Synthesis, Characterization, and Electrochemical Behavior of LiMnFePO₄ Composites Obtained from Phenylphosphonate-Based Organic-Inorganic Hybrids.

The synthesis of organic-inorganic hybrid compounds based on phenylphosphonate and their use as precursors to form LiMnFePO₄ composites containing carbonaceous substances with sub-micrometric morphology are presented. The experimental procedure includes the preliminary synthesis of Fe and/or Mn phenylphosphonates with the general formula FeMn[(C₆H₅PO₃)(H₂O)] (with 0 < x < 1), which are then mixed at different molar ratios with lithium carbonate. In this way the carbon, obtained from in situ partial oxidation of the precursor organic part, coats the LiMnFePO₄ particles. After a structural and morphological characterization, the electrochemical behavior of lithium iron manganese phosphates has been compared to the one of pristine LiFePO₄ and LiMnPO₄, in order to evaluate the doping influence on the material.