Synthesis of lithium-iron-phosphates under hydrothermal conditions

摘要

The present invention relates to a process for the preparation of compounds of general formula (I) Lia-bMb1Fe1-cMc2Pd-eMe3Ox, wherein Fe has the oxidation state +2 and M1, M2, M3, a, b, c, d, e and x are: M1: Na, K, Rb and/or Cs, M2: Mn, Mg, Al, Ca, Ti, Co, Ni, Cr, V, 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 iron-comprising compound, in which iron has the oxidation state 0, 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 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 obtain a compound of general formula (I).

主权项

1. A process for preparing at least one compound of formula (I), the process comprising:
heating an essentially aqueous mixture comprising at least one lithium-comprising compound, at least one iron-comprising compound in which iron has the oxidation state 0, at least one compound comprising at least one phosphorous atom in oxidation state +5, and, optionally, at least one selected from the group consisting of an M1-comprising compound, an M2-comprising compound, and an M3-comprising compound, at a temperature of 100 to 500° C. and at an autogeneous pressure to obtain the at least one compound of formula (I)
Lia-bMb1Fe1-cMc2Pd-eMe3Ox  (I), wherein Fe has the oxidation state +2, M1 is at least one selected from the group consisting of Na, K, Rb, and Cs, M2 is Mn, Mg, Al, Ca, Ti, Co, Ni, Cr, or V, M3 is Si, S, or F, a is 0.8-1.9, b is 0-0.3, c is 0-0.9, d is 0.8-1.9, e is 0-0.5, and x is 1.0-8, depending on an amount and oxidation state of Li, M1, M2, P, M3, and wherein compounds of formula (I) are neutrally charged.