Carbon-deposited alkali metal oxyanion electrode material and process for preparing same

Abstract

The present invention relates to a process for the synthesis of a carbon-deposited alkali metal oxyanion cathode material comprising particles, wherein said particles carry, on at least a portion of the particle surface, carbon deposited by pyrolysis, said process comprising a dry high-energy milling step performed on precursors of said carbon-deposited alkali metal oxyanion prior to a solid-state thermal reaction.

1 . A process for the synthesis of a carbon-deposited alkali metal oxyanion cathode material comprising particles, wherein said particles carry, on at least a portion of the particle surface, carbon deposited by pyrolysis, said process comprising:
 a first dry high-energy milling step performed on precursors of said carbon-deposited alkali metal oxyanion prior to a first solid-state thermal reaction, wherein said first solid-state thermal reaction produces a first solid-state thermal reaction product; and   a second dry high-energy milling step performed on said product prior to a second solid-state thermal reaction.   
     
     
         2 . The process of  claim 1 , wherein said process comprises adding a source compound of carbon (i) prior to and/or during said first high-energy milling step and/or (ii) prior to and/or during said second high-energy milling step. 
     
     
         3 . The process of  claim 2 , wherein said carbon source is a liquid, solid or gaseous hydrocarbon. 
     
     
         4 . The process of  claim 2 , wherein said carbon source is selected from the group consisting of polycyclic aromatic entities, perylene and its derivatives, polyhydric compounds, cellulose, starch and their esters and ethers, fatty acid, fatty acid salts, fatty acid esters, fatty alcohol, fatty alcohol esters, alkoxylated alcohols, alkoxylated amines, fatty alcohol sulfate, phosphate esters, imidazolium and quaternary ammonium salts, ethylene oxide/propylene oxide copolymer, ethylene oxide/butylene oxide copolymer, polyolefins, polybutadienes, polyvinyl alcohol, condensation products of phenols, and polymers derived from furfuryl alcohol, from styrene, from divinylbenzene, from naphthalene, from perylene, from acrylonitrile and from vinyl acetate. 
     
     
         5 . The process of  claim 4 , wherein said polycyclic aromatic entities are selected from the group consisting of tar and pitch. 
     
     
         6 . The process of  claim 4 , wherein said polyhydric compounds are selected from the group consisting of sugars, carbohydrates, and their derivatives. 
     
     
         7 . The process of  claim 1 , wherein said precursors are provided in totality prior to said first solid-state thermal reaction, or a part thereof is provided prior to each solid-state thermal reaction. 
     
     
         8 . The process of  claim 1 , wherein said precursors comprise at least one source compound of an alkali metal, at least one source compound of Fe and/or Mn; at least one source compound of a metal M′, where M′ is a 2+ or more metal in the carbon-deposited alkali metal oxyanion; at least one source compound of said oxyanion, if the oxyanion is not present in another source compound; and at least one source of carbon. 
     
     
         9 . The process of  claim 8 , wherein said source compound of said oxyanion comprises at least a source compound of phosphorus (P), if the element P is not present in another source compound; and/or at least one source compound of silicon (Si) if the element Si is not present in another source compound. 
     
     
         10 . The process of  claim 8 , wherein said source compound of Fe is selected from the group consisting of iron, iron (III) oxide, magnetite (Fe 3 O 4 ), trivalent iron phosphate, lithium iron hydroxyphosphate, trivalent iron nitrate, ferrous phosphate, vivianite Fe 3 (PO 4 ) 2 , iron acetate (CH 3 COO) 2 Fe, iron sulfate (FeSO 4 ), iron oxalate, iron (III) nitrate, iron (II) nitrate, FeCl 3 , FeCl 2 , FeO, ammonium iron phosphate (NH 4 FePO 4 ), Fe 2 P 2 O 7 , ferrocene, and any combinations thereof. 
     
     
         11 . The process of  claim 8 , wherein said source compound of Mn is selected from the group consisting of manganese, MnO, MnO 2 , manganese acetate, manganese oxalate, Mn (III) acetylacetonate, Mn (II) acetylacetonate, Mn (II) chloride, MnCO 3 , manganese sulfate, manganese nitrate, manganese phosphate, manganocene, and any combinations thereof. 
     
     
         12 . The process of  claim 8 , wherein said source compound of alkaline metal is selected from the group consisting of lithium oxide, sodium oxide, lithium hydroxide, sodium hydroxide, potassium hydroxide, lithium carbonate, sodium carbonate, potassium carbonate, Li 3 PO 4 , Na 3 PO 4 , K 3 PO 4 , the hydrogen phosphate LiH 2 PO 4 , LiNaHPO 4 , LiKHPO 4 , NaH 2 PO 4 , KH 2 PO 4 , Li 2 HPO 4 , lithium, sodium or potassium ortho-, meta- or polysilicates, lithium sulfate, sodium sulfate, potassium sulfate, lithium oxalate, sodium oxalate, potassium oxalate, lithium acetate, sodium acetate, potassium acetate, and any combinations thereof. 
     
     
         13 . The process of  claim 8 , wherein said oxyanion comprises a phosphorus and said source compound of oxyanion is selected from the group consisting of phosphoric acid and its esters, M 3 PO 4  wherein M is at least one selected from Li, Na and K, the hydrogen phosphate MH 2 PO 4  wherein M is at least one selected from Li, Na and K, monoammonium or diammonium phosphates, trivalent iron phosphate or manganese ammonium phosphate (NH 4 MnPO 4 ), MnHPO 4 , Fe 2 P 2 O 7 , and any combinations thereof. 
     
     
         14 . The process of  claim 8 , wherein said oxyanion comprises a Si and said source compound of oxyanion is selected from the group consisting of organosilicon, silicon alkoxides, tetraalkyl orthosilicate, tetraethyl orthosilicate, nanosized SiO 2 , Li 2 SiO 3 , Li 4 SiO 4 , and any combinations thereof. 
     
     
         15 . The process of  claim 8 , wherein said source compound of M′ is a source compound of a metal selected from the group consisting of Zr 4+ , Ti 4+ , Nb 4+ , Mo 4+ , Ge 4+ , Ce 4+  and Sn 4+ , and/or a source compound of a metal selected from the group consisting of Al 3+ , Y 3+ , Nb 3+ , Ti 3+ , Ga 3+ , Cr 3+  and V 3+ , and/or a source compound of a metal selected from the group consisting of Ta 5+  and Nb 5+ , and/or a source compound of a metal selected from the group consisting of Zn 2+  and Ca 2+ . 
     
     
         16 . The process of  claim 15 , wherein said metal is Zr 4+  and said source compound is selected from the group consisting of zirconium acetate hydroxide, zirconium alkoxide, n-butyl zirconate, zirconium (IV) acetylacetonate, zirconium (IV) ethoxide, zirconium (IV) hydrogenphosphate, zirconium (IV) silicate and any combinations thereof. 
     
     
         17 . The process of  claim 8 , wherein said oxyanion comprises P and Si and said source compounds are selected to provide a cathode material having an alkali metal:M:M′:P:Si ratios of about 1:0.7 to 1:>0 to 0.3:>0.7 to 1:>0 to 0.3. 
     
     
         18 . The process of  claim 1 , wherein said dry high-energy milling is performed with a milling apparatus selected from the group consisting of a high-energy ball mill, a pulverizing mixer mill, a planetary ball mill, a drum/ball-mill, a shaker mill, a stirred ball mill, a mixer ball mill, a vertical attritor, a horizontal attritor and any combinations thereof. 
     
     
         19 . The process of  claim 1 , wherein said first solid-state thermal reaction is operated at a temperature selected from the range of temperatures between about 200° C. and about 600° C. 
     
     
         20 . The process of  claim 1 , wherein said second solid-state thermal reaction is operated at a temperature selected from the range of temperatures between about 400° C. and about 800° C. 
     
     
         21 . The process of  claim 1 , wherein said first and/or second solid-state thermal step(s) is performed under an inert or reductive atmosphere, wherein said atmosphere is optionally humidified. 
     
     
         22 . The process of  claim 1 , wherein said first and/or second high-energy milling step(s) is performed under an inert or reductive atmosphere. 
     
     
         23 . The process of  claim 21 , wherein said reductive atmosphere participates in the reduction or prevents the oxidation of the oxidation state of at least one metal in the precursors without full reduction to an elemental state. 
     
     
         24 . The process of  claim 23 , wherein said reductive atmosphere comprises an externally applied reductive atmosphere, a reductive atmosphere derived from the degradation of a compound, a reductive atmosphere derived from the synthesis reaction, or any combinations thereof. 
     
     
         25 . The process of  claim 24 , wherein said externally applied reductive atmosphere comprises CO, H 2 , NH 3 , HC, and any combinations thereof, wherein HC is a hydrocarbon or carbonaceous product. 
     
     
         26 . The process of  claim 24 , wherein said reductive atmosphere derived from the degradation of a compound comprises a reductive atmosphere which is produced when the compound is degraded or is transformed under heat. 
     
     
         27 . The process of  claim 24 , wherein said reductive atmosphere derived from the degradation of a compound comprises CO, CO/CO 2 , H 2  or any combinations thereof. 
     
     
         28 . The process of  claim 1 , wherein said precursors comprise an iron source comprising FePO 4  and/or iron oxalate, a lithium compound comprising Li 2 CO 3  and/or LiH 2 PO 4 , a source of Si and a source of Zr (IV). 
     
     
         29 . A process for the synthesis of a carbon-deposited alkali metal oxyanion cathode material comprising particles, wherein said particles carry, on at least a portion of the particle surface, carbon deposited by pyrolysis, said process comprising a dry high-energy milling step performed on precursors of said alkali metal oxyanion prior to a solid-state thermal reaction. 
     
     
         30 . A process as defined in  claim 29 , wherein said solid-state thermal reaction produces a solid-state thermal reaction product; and wherein a second high-energy milling step is performed on said product prior to a second solid-state thermal reaction. 
     
     
         31 . A carbon-deposited alkali metal phosphosilicate cathode material, comprising particles having an olivine structure and which carry, on at least a portion of their surface, carbon deposited by pyrolysis, wherein the particles have a general formula in which the elements Li:Fe:M′:PO 4 :SiO 4  are present at about 1+/− x:0.95+/− x:0.05+/− x:0.95+/− x:0.05+/− x ratios, where x is independently about 20% of value and wherein the M′ is a 4+ valency metal. 
     
     
         32 . The carbon carbon-deposited alkali metal phosphosilicate cathode material of  claim 31 , wherein x is independently about 10% of value. 
     
     
         33 . The carbon carbon-deposited alkali metal phosphosilicate cathode material of  claim 31 , wherein x is independently about 5% of value. 
     
     
         34 . The carbon carbon-deposited alkali metal phosphosilicate cathode material of  claim 31 , wherein x is independently about 4% of value. 
     
     
         35 . The carbon carbon-deposited alkali metal phosphosilicate cathode material of  claim 31 , wherein x is independently about 3% of value. 
     
     
         36 . The carbon carbon-deposited alkali metal phosphosilicate cathode material of  claim 31 , wherein x is independently about 2% of value. 
     
     
         37 . The carbon carbon-deposited alkali metal phosphosilicate cathode material of  claim 31 , wherein the M′ is Zr 4+ . 
     
     
         38 . The carbon-deposited alkali metal phosphosilicate cathode material of  claim 31 , wherein M′ is Zr 4+  and wherein the particles have a general formula in which the elements Li:Fe:Zr:PO 4 :SiO 4  are present at about 1:0.95:0.05:0.95:0.05 ratios. 
     
     
         39 . The process of  claim 1 , wherein said first thermal reaction produces a substantially amorphous product and/or wherein the second high-energy milling produces a substantially amorphous product. 
     
     
         40 . The process of  claim 1 , wherein said carbon-deposited alkali metal oxyanion cathode material is a carbon-deposited alkali metal phosphosilicate cathode material. 
     
     
         41 . The process of  claim 1 , wherein said high-energy milling is high-energy ball milling. 
     
     
         42 . The process of  claim 1 , wherein said first solid-state thermal step is operated at a temperature selected from the range of temperatures between about 400° C. and about 600° C., or about 200° C. and about 500° C., or about 250° C. and about 450° C., or about 300° C. and about 400° C. 
     
     
         43 . The process of  claim 1 , wherein said second solid-state thermal step is operated at a temperature selected from the range of temperatures between about 400° C. and about 700° C., or about 450° C. and about 650° C., or about 500° C. and about 600° C. 
     
     
         44 . The process of  claim 1 , wherein said first and/or second high-energy milling step that is performed during a time period selected from the following time ranges of between about 5 minutes to about 4 hours, about 10 minutes to about 4 hours, about 30 minutes to about 4 hours, about 60 minutes to about 4 hours, about 90 minutes to about 4 hours, about 120 minutes to about 4 hours, about 150 minutes to about 4 hours, about 180 minutes to about 4 hours, about 210 minutes to about 4 hours, or about 230 minutes to about 4 hours. 
     
     
         45 . The process of  claim 1 , further comprising a subsequent flash thermal treatment which is operated at a temperature selected from the following temperature ranges of between about 650° C. and about 900° C., about 700° C. and about 900° C., about 750° C. and about 900° C., about 800° C. and about 900° C., or about 825° C. and about 900° C., or about 850° C. and about 900° C.