SYNTHESIS OF LITHIUM-METAL-PHOSPHATES UNDER HYDROTHERMAL CONDITIONS

摘要

The present invention relates to a process for the preparation of compounds of general formula (I) Lia-bM1 bQ1-cM2 cPd-eM3 eOx (l), wherein Q has the oxidation state +2 and M1, M2, M3, a, b, c, d, e and x are: Q: Fe, Mn, Co, Ni, M1 : Na, K, Rb and/or Cs, M2: Mg, Al, Ca, Ti, Co, Ni, Cr, V, Fe, Mn, wherein Q and M2 are different from each other, M3: Si, S, F a: 0.8 - 1.9, b: 0 - 0.3, c: 0 - 0.9, d: 0.8 - 1.9, e: 0 - 0.5, x: 1.0 - 8, depending on the amount and oxidation state of Li, M1, M2, P, M3, wherein compounds of general formula (I) are neutrally charged, comprising the following steps (A) providing a mixture comprising at least one lithium-comprising compound, at least one Q-comprising compound, in which Q has at least partially an oxidation state higher than +2, and at least one M1-comprising compound, if present, and/or at least one M2-comprising compound, if present, and/or least one M3-comprising compound, if present, and at least one reducing agent which is oxidized to at least one compound comprising at least one phosphorous atom in oxidation state +5, and (B) heating the mixture obtained in step (A) at a temperature of 100 to 500 °C and at an autogeneous pressure to reduce Q to oxidation state +2 and to obtain a compound of general formula (I).