Patent ID: 7601318

Claim:
A method for the synthesis of compounds of the formula C—Li x M 1−y M′ y (XO 4 ) n , wherein C represents carbon cross-linked with the compound of formula Li x M 1−y M′ y (XO 4 ) n , wherein 0≦x≦2, ≦y≦0.6, and 1≦n≦1.5, M is at least one transition metal selected from the first line of the periodic table, M′ is an element with a fixed valency selected from the group consisting of Mg 2+ , Ca 2+ , Al 3+ , Zn 2+ and combinations thereof and X is S, P or Si, said method comprising: bringing into equilibrium in the required proportions, for a duration of less than 5 hours, a mixture comprising the following precursors: a) a source of M comprising at least one transition metal or at least one salt thereof; b) a source of the element M′ that is a salt of M′; c) a source of lithium that is a salt of lithium; d) a compound that is a source of X; and e) a source of a carbon conductor that is an organic substance, wherein the source of M and the source of M′, if any, is in the form of precursor particles having a size of between 0.1 micrometer to 6 micrometer, wherein the precursor particles are made up of agglomerates of nanoparticles on the order of 50 nm to 100 nm, wherein the sources of the elements M, M′, Li and X are introduced, in whole or in part, in at least one step, in the form of compounds having more than one source element, wherein the precursors a) to d) are mixed intimately, and wherein a synthesis reaction is carried out by thermodynamic or kinetic reaction and bringing into equilibrium, in the required proportions, the mixture of the precursors a) to d), with a gaseous reducing atmosphere to provide an oxidation state of the transition metal of the desired valency for the formation of Li x M 1−y M′ y (XO 4 ) n , by controlling the composition of said gaseous atmosphere, the temperature of the synthesis reaction step, and the amount of precursor c) relative to the amount of precursors a), b) and d); the method further comprising at least one pyrolysis step of the source compound e) so as to obtain a carbon conductor with an electronic conductivity greater than 10 −8 S·cm −1 , when measured on a sample of powder compressed at a pressure greater than or equal to 3000 Kg·cm −2 , wherein the synthesis reaction between the precursors a) to d) is carried out simultaneously with the pyrolysis reaction of the precursor e).