Method for the manufacture of cathode materials
A method of producing a particulate lithium metal oxide cathode material comprising the steps of providing an organic acid, providing a lithium compound, and providing a metal compound. The organic acid, the lithium compound, and the metal compound are mixed to form a mixture. The organic acid is melted to form a liquid organic acid, if the organic acid is provided as a solid. The mixture, including the liquid organic acid, is calcined in an atmosphere containing oxygen to form a lithium metal oxide. The lithium metal oxide is cooled and sized to produce the particulate lithium metal oxide having a predetermined average particle size.
1 . A method of producing a particulate lithium metal phosphate Li(M5)PO 4 , the method comprising:
providing an apparatus;
adding a solid organic acid to the apparatus;
adding a lithium compound Li x1 (A) where x1 is 1-3 to the apparatus;
adding a phosphate-containing compound to the apparatus;
adding a metal compound (M5)(A) x where x is 1 or 2 to the apparatus;
mixing the solid organic acid, the lithium compound, the phosphate-containing compound and the metal compound in the apparatus to form a mixture;
melting the solid organic acid in the apparatus to form a liquid organic acid;
calcining the mixture, including the liquid organic acid, in an inert gas to yield a lithium metal phosphate;
cooling the lithium metal phosphate; and
sizing the cooled lithium metal phosphate to produce the particulate lithium metal phosphate having a predetermined average particle size.
2 . The method of claim 1 , wherein the melting step is performed before the mixing step.
3 . The method of claim 1 , wherein the mixing step is performed before the melting step.
4 . The method of claim 1 , wherein the melting step and calcining step are achieved by a gradual addition of heat, so as to first melt the organic acid and then calcine the mixture, including the liquid organic acid.
5 . The method of claim 1 , wherein the mixing step, the melting step and the calcining step are performed in the apparatus.
6 . The method of claim 5 , wherein the apparatus is a rotary calciner.
7 . The method of claim 1 , wherein M5 is selected from the group consisting of iron, nickel, manganese, or cobalt.
8 . The method of claim 1 , wherein A is an anionic component that is selected from the group consisting of hydroxide, carbonate, acetate, alkoxide, oxalate, nitrate, nitride, sulfate, acetylacetonate, and oxide.
9 . The method of claim 1 , wherein the phosphate-containing compound is selected from the group consisting of (NH 4 ) 3 PO 4 , H 3 PO 4 , Na 3 PO 4 , Li 3 PO 4 , K 3 PO 4 , H(NH 4 ) 2 PO 4 , and H 2 (NH 4 )PO 4 .
10 . The method of claim 1 , further combining one or more additional metal compounds with the liquid organic acid to form a lithium mixed metal phosphate.
11 . The method of claim 10 , wherein the lithium mixed metal phosphate has the general formula Li(M5) a (M6) b PO 4 where a+b=1, Li(M5) a (M6) b (M7) c PO 4 where a+b+c=1, or Li(M5) a (M6) b (M7) c (M8) d PO 4 where a+b+c+d=1.
12 . The method of claim 11 , wherein M5, M6, M7, and M8 are selected from the group consisting of iron, nickel, manganese, and cobalt.