Patent ID: 8652431

Claim:
Method of synthesis of a metal fluorophosphate having the following general formula (1): X a M b (PO 4 ) c F d (1) in which: X is an alkaline metal selected among sodium (Na) and lithium (Li) or a mixture of said metals; M is a transition metal selected among the following elements: Co, Ni, Fe, Mn, V, Cu, Ti, Al, Cr, Mo, Nb or a combination of at least two of said metals, 0≦a≦5; 0.5≦b≦3; 0.5≦c≦3; and d is an integer equal to 1, 2 or 3, X, M, PO 4 , F, a, b, c, d being chosen in order to maintain the electroneutrality of the metal fluorophosphate, wherein said method includes a heat treatment of a mixture of solid precursors (1) of said metal fluorophosphate, formed by at least one first phosphate-containing precursor and at least one second fluorine-containing precursor and in that the heat treatment is an electric-field-activated sintering process during which it is applied to said mixture, simultaneously, a pressure between 0.5 MPa and 200 MPa and an electrical current heating said mixture with a mean temperature rising rate between 50° C/min −1 and 600° C/min −1 .