Substituted lithium-manganese metal phosphate
View Patent ↗A substituted lithium-manganese metal phosphate of formula LiFe x Mn 1-x-y M y PO 4 in which M is a bivalent metal from the group Sn, Pb, Zn, Ca, Sr, Ba, Co, Ti and Cd and wherein: x<1, y<0.3 and x+y<1, a process for producing it as well as its use as cathode material in a secondary lithium-ion battery.
1. A lithium-manganese metal phosphate of formula
LiFe x Mn 1-x-y M y PO 4
wherein M is a bivalent metal selected from the group consisting of Zn, Ca, and Cd, and
wherein: x<1, 0<y<0.15 and x+y<1.
2. The lithium-manganese metal phosphate according to claim 1 , wherein M is Zn or Ca.
3. The lithium-manganese metal phosphate according to claim 1 , further comprising carbon.
4. The lithium-manganese metal phosphate according to claim 3 , wherein the carbon is evenly distributed throughout the lithium-manganese metal phosphate.
5. The lithium-manganese metal phosphate according to claim 3 , wherein the carbon covers the individual particles of the lithium manganese metal phosphate.
6. The lithium-manganese metal phosphate according to claim 3 , wherein the proportion of carbon relative to the lithium manganese metal phosphate is <4 wt %.
7. Cathode for a secondary lithium-ion battery, comprising the lithium-manganese metal phosphate according to claim 1 .
8. The cathode according to claim 7 , further comprising a lithium-metal-oxygen compound.
9. The cathode according to claim 8 , wherein the lithium-metal-oxygen compound is selected from the group consisting of LiCoO 2 , LiMn 2 O 4 , LiNiO 2 , LiCoPO 4 , LiFePO 4 , LiMnPO 4 , LiMnFePO 4 , and mixtures thereof.
10. The cathode according to claim 7 , wherein the cathode is free of added conductive agents.
11. Process for producing the lithium-manganese metal phosphate according to claim 1 , the process comprising the following steps:
a) producing a mixture in aqueous solution containing at least a Li starting compound, a Mn starting compound, an Fe starting compound, a M 2+ starting compound and a PO 4 3− starting compound, until a suspension forms,
b) carrying out a dispersion or grinding treatment of the mixture and/or the suspension,
c) obtaining a lithium-manganese metal phosphate of formula LiFe x Mn 1-x-y M y PO 4 from the suspension by reaction of the suspension under hydrothermal conditions.
12. The process according to claim 11 , further comprising, in step a) or step c), adding a carbon-containing component.
13. The process according to claim 12 , further comprising mixing the lithium-manganese metal phosphate of formula LiFe x Mn 1-x-y M y PO 4 obtained in step c) with a carbon-containing component.
14. The process according to claim 11 , further comprising carrying out a drying step at a temperature of <100° C. and/or a calcining step at a temperature of >200° C.
15. The process according to claim 11 , wherein the process is carried out under hydrothermal conditions at a temperature of 100° C. to 200° C. and at a pressure of 1 bar to 40 bar vapour pressure.
16. Lithium-manganese metal phosphate produced by the process according to claim 11 .