Stable lithium fluoride-based cathodes for metal and metal-ion batteries
A battery electrode composition is provided that comprises composite particles. Each composite particle may comprise, for example, active lithium fluoride/metal nanocomposite material optionally embedded into a nanoporous, electrically-conductive skeleton matrix material particle(s), where each of these composite particles is further encased in a Li-ion permeable, chemically and mechanically robust, protective outer shell that is impermeable to electrolyte solvent molecules. The active lithium fluoride/metal nanocomposite material is provided to store and release Li ions during battery operation.
1. A Li or Li-ion battery electrode composition comprising:
a powder or slurry comprising a composite particle that includes:
a mixture of metal and lithium fluoride (LiF) materials capable of storing and releasing Li ions during battery operation;
a skeleton matrix material into which the mixture is embedded to form an active material core; and
a Li-ion permeable shell at least partially encasing the active material core and protecting the metal and LiF materials from interaction with a battery electrolyte.
2. The battery electrode composition of claim 1 , wherein the composite particle is of a substantially-spherical shape and exhibits a diameter in the range of about 50 nm to about 10 microns.
3. The battery electrode composition of claim 1 , wherein the Li-ion permeable shell has an average shell thickness in the range of about 1 nm to about 100 nm.
4. The battery electrode composition of claim 1 , wherein the skeleton matrix material makes up a volume fraction of the composite particle in the range of about 3 vol. % to about 40 vol. %.
5. The battery electrode composition of claim 4 , wherein the volume fraction of the skeleton matrix material near the perimeter of the composite particle is at least 10% larger than in the center of the composite particle.
6. The battery electrode composition of claim 1 , wherein the skeleton matrix material is in the form of a monolithic particle.
7. The battery electrode composition of claim 1 , wherein the skeleton matrix material comprises about 20 at. % to about 100 at. % carbon.
8. The battery electrode composition of claim 1 , wherein the skeleton matrix material comprises more than about 0.05 at. % fluorine.
9. The battery electrode composition of claim 1 , wherein the metal of the mixture comprises at least 10 at. % Cu and at most 90 at. % of at least one of the following: Fe, Co, Ni, Ti, Zn, Bi, Pb, Sb, Sn, Cd, Cr, Zr, Nb, Mo, Hf, Ta, Si, La, or Ce.
10. The battery electrode composition of claim 1 , wherein the Li-ion permeable shell is a composite material that has at least two components.
11. The battery electrode composition of claim 1 , wherein the Li-ion permeable shell comprises about 20 at. % to about 100 at. % carbon.
12. The battery electrode composition of claim 1 , wherein the composite particle further comprises one or more functional groups forming a coating on the Li-ion permeable shell.
13. A Li or Li-ion battery, comprising:
anode and cathode electrodes, wherein the cathode electrode comprises the battery electrode composition of claim 1 ;
an electrolyte ionically coupling the anode and cathode electrodes; and
a separator electrically separating the anode and cathode electrodes.
14. A method of fabricating a Li or Li-ion battery electrode composition comprising a composite particle, the method comprising:
embedding one or more metal, metal oxide, or metal salt precursors into a skeleton matrix material;
inducing conversion of the one or more precursors into a metal fluoride embedded into the skeleton matrix material via a fluorination reaction to form an active material core; and
after the inducing, at least partially encasing the active material core with a Li-ion permeable shell to protect the active material core from interaction with a battery electrolyte,
wherein, after the inducing, the at least partially encased active material core is arranged as a powder or as part of a slurry.
15. The method of claim 14 , wherein the one or more precursors comprise a mixture of two different precursor compositions.
16. The method of claim 14 , wherein a plasma source is utilized for the formation of fluorine radicals involved in the fluorination reaction.
17. The method of claim 14 , further comprising chemical lithiation of the metal fluoride embedded into the skeleton matrix material.
18. The method of claim 17 , wherein the chemical lithiation proceeds by using one or more chemical lithiation reagents that are soluble in organic solvents.
19. The method of claim 18 , wherein the one or more chemical lithiation reagents comprise at least one of the following: (i) a lithium alkylborohydride, (ii) an alkyllithium magnesate, (iii) a radical anion of polycyclic aromatic hydrocarbons, (iv) a lithium ketone radical anion, or (v) a lithium aluminum hydride.
20. The method of claim 18 , wherein the one or more chemical lithiation reagents comprise (i) lithium borohydride or (ii) an alkyllithium reagent.
21. The method of claim 18 , wherein the fluorination reaction comprises using a non-lithium-containing reducing agent to reduce metal ions in a metal fluoride composition to a corresponding metallic state and a separate lithium-containing salt to provide lithium ions to form lithium fluoride (LiF).