Methods of making lithium vanadium oxide powders and uses of the powders
View Patent ↗Methods relate to making lithium vanadium oxide powders. Applications for the lithium vanadium oxide powders include use as a negative electrode or anode material for lithium ion batteries. Liquid phase reactions and reduction in vanadium oxidation state of precursor material facilitate in the making of the lithium vanadium oxide powders. Particles forming the lithium vanadium oxide powders may further contain carbon to provide electrical conductivity.
1. A method comprising the steps of:
preparing a liquid mixture comprising a reducing agent, vanadium pentoxide, and lithium ions from a lithium salt; and
forming lithium vanadium oxide by subjecting the mixture to conditions that permit reduction of the vanadium pentoxide by the reducing agent for precipitation of lithium vanadium oxide particles, wherein the particles have a formula defined as Li 1+x VO 2 , where x is a number from 0 to 0.5.
2. The method according to claim 1 , wherein forming the particles includes heating the mixture that has a molar ratio of lithium to vanadium within the mixture from 1.5 to 1 while forming the particles.
3. The method according to claim 1 , wherein the lithium salt comprises at least one of lithium carbonate and lithium hydroxide.
4. The method according to claim 1 , wherein the reducing agent is n-methyl-pyrrolidinone.
5. The method according to claim 1 , wherein the lithium salt comprises at least one of lithium carbonate and lithium hydroxide and the reducing agent is n-methyl-pyrrolidinone.
6. The method according to claim 1 , further comprising crystallizing the particles by heating the particles at a temperature above 1000° C.
7. The method according to claim 1 , wherein x is 0.2.
8. The method according to claim 1 , wherein the reducing agent is an organic compound.
9. The method according to claim 1 , wherein the mixture further comprises a carbon-residue-forming material.
10. The method according to claim 1 , further comprising:
coating the particles with a carbon-residue-forming material; and
heating in an inert environment the particles that are coated, wherein the heating is at a temperature sufficient to carbonize the carbon-residue-forming material.
11. The method according to claim 1 , further comprising:
oxidizing the reducing agent, wherein the reducing agent is n-methyl-pyrrolidinone and remains on the particles after evaporation of liquids from the mixture to form a coating that is between 1 and 10 weight percent of the particles; and
heating the coating in an inert environment at a temperature sufficient to carbonize the coating on the particles.
12. A method comprising the steps of:
preparing a liquid mixture comprising n-methyl-pyrrolidinone, vanadium pentoxide, and lithium ions from at least one of lithium carbonate and lithium hydroxide;
forming lithium vanadium oxide by heating the mixture such that the n-methyl-pyrrolidinone reduces vanadium oxidation state from 5+ to a lower oxidation state for precipitation of lithium vanadium oxide particles, wherein during the heating a molar ratio of lithium to vanadium within the mixture is from 1.5 to 1 and the particles have a formula of Li 1+x VO 2 , where x is a number from 0 to 0.5; and
incorporating the particles into an anode of a battery.
13. The method according to claim 12 , wherein the mixture further comprises at least one of a material selected from the group consisting of petroleum pitches and chemical process pitches, coal tar pitches, lignin from pulp industry, phenolic resins and combinations thereof.
14. The method according to claim 12 , further comprising heating the particles removed from the mixture to carbonize a material that is part of the particles, wherein the material is selected from the group consisting of petroleum pitches and chemical process pitches, coal tar pitches, lignin from pulp industry, phenolic resins and combinations thereof.