Electrode materials for rechargeable battery
A positive electrode is disclosed for a non-aqueous electrolyte lithium rechargeable cell or battery. The electrode comprises a lithium containing material of the formula Na y Li x Ni z Mn 1-z-z′ M z′ O d , wherein M is a metal cation, x+y>1, 0<z<0.5, 0≤z′<0.5, y+x+1 is less than d, and the value of d depends on the proportions and average oxidation states of the metallic elements, Li, Na, Mn, Ni, and M, if present, such that the combined positive charge of the metallic elements is balanced by the number of oxygen anions, d. The inventive material preferably has a spinel or spinel-like component in its structure. The value of y preferably is less than about 0.2, and M comprises one or more metal cations selected preferably from one or more monovalent, divalent, trivalent or tetravalent cations, such as Mg 2+ , Co 2+ , Co 3+ , B 3+ , Ga 3+ , Fe 2+ , Fe 3+ , Al 3+ , and Ti 4+ . The electrode material can be synthesized using an ion-exchange reaction with a lithium salt in an organic-based solvent to partially replace sodium ions of a precursor material with lithium ions.
1. A metal oxide precursor composition useful for preparing an electrode for a lithium electrochemical cell, the precursor composition comprising Na y′ Li x′ Ni z Mn 1-z-z′ M z′ O d′ , wherein y′+x′>1, 0<z<0.5, 0<z′<0.5, y′+x′+1 is less than d′, and the value of d′ depends on the proportions and average oxidation states of the metallic elements, Li, Na, Mn, Ni, and M, if present, such that the combined positive charge of the metallic elements is balanced by the number of oxygen anions, d′; wherein the metal oxide precursor composition has a layered structure; and M is at least one cation selected from the group consisting of Mg 2+ , B 3+ , Ga 3+ , Al 3+ , and Ti 4+ .
2. A metal oxide precursor composition useful for preparing an electrode for a lithium electrochemical cell, the precursor composition comprising Na y′ Li x′ Ni z Mn 1-z-z′ M z′ O d′ wherein M comprises one or more metal cation; y′+x′=1.2; 0<z<0.5; 0≤z′<0.5; 0.1≤x′≤0.3; 0.9≤y′≤1.1; y′+x′+1 is less than d′; and the value of d′ depends on the proportions and average oxidation states of the metallic elements, Li, Na, Mn, Ni, and M, if present, such that the combined positive charge of the metallic elements is balanced by the number of oxygen anions, d′; and wherein the metal oxide precursor composition has a layered structure.
3. The composition of claim 2 , wherein M is at least one cation selected from the group consisting of Mg 2+ , B 3+ , Co 2+ , Co 3+ , Ga 3+ , Fe 2+ , Fe 3+ , Al 3+ , and Ti 4+ .
4. The composition of claim 2 , wherein the Na y′ Li x′ Ni z Mn 1-z-z′ M z′ O d′ is at least one metal oxide selected from the group consisting of Na 1.0 Li 0.2 (Ni 0.25 Mn 0.75 )O d′ , Na 1.1 Li 0.1 Ni 0.25 Mn 0.75 O d′ , and Na 0.9 Li 0.3 Ni 0.25 Mn 0.75 O d .
5. A metal oxide precursor composition useful for preparing an electrode for a lithium electrochemical cell, the precursor composition comprising Na y′ Li x′ Ni z Mn 1-z-z′ M z′ O d′ wherein y′+x′>1, 0≤z<0.5, 0<z′<0.5, y′+x′+1 is less than d′, and the value of d′ depends on the proportions and average oxidation states of the metallic elements, Li, Na, Mn, Ni, and M, if present, such that the combined positive charge of the metallic elements is balanced by the number of oxygen anions, d′; wherein the metal oxide precursor composition has a layered structure; and wherein the Na y′ Li x′ Ni z Mn 1-z-z′ M z′ O d′ is selected from the group consisting of Na 1.0 Li 0.2 Ni 0.25 Mn 0.75 O d′ , Na 1.1 Li 0.1 Ni 0.25 Mn 0.75 O d′ , and Na 0.9 Li 0.3 Ni 0.25 Mn 0.75 O d .
6. A process of preparing a composition of claim 1 , comprising pyrolyzing a mixture of materials comprising a source of oxygen anions and heat decomposable compounds of Li, Na, Ni, Mn and M.
7. The process of claim 6 , wherein the heat decomposable compounds are powdered carbonates comprising a mixture of Na 2 CO 3 , Li 2 CO 3 and (Ni,Mn,M)CO 3 or a mixture of Na 2 CO 3 , Li 2 CO 3 , (Ni,Mn)CO 3 and MCO 3 .
8. The process of claim 6 , wherein the pyrolyzing comprises heating the mixture of compounds at a temperature in excess of about 500° C.
9. A process of preparing a composition of claim 3 , comprising pyrolyzing a mixture of materials comprising a source of oxygen anions and heat decomposable compounds of Li, Na, Ni, Mn, and optionally M, when M is present.
10. The process of claim 9 , wherein the heat decomposable compounds are powdered carbonates comprising a mixture of Na 2 CO 3 , Li 2 CO 3 , and (Ni,Mn,M)CO 3 ; or a mixture of Na 2 CO 3 , Li 2 CO 3 , (Ni,Mn)CO 3 and MCO 3 .
11. The process of claim 9 , wherein the pyrolyzing comprises heating the mixture of compounds at a temperature in excess of about 500° C.
12. A process of preparing a composition of claim 5 , comprising pyrolyzing a mixture of materials comprising a source of oxygen anions and heat decomposable compounds of Li, Na, Ni, Mn, and optionally M, when M is present.
13. The process of claim 12 , wherein the heat decomposable compounds are powdered carbonates comprising a mixture of Na 2 CO 3 , Li 2 CO 3 , and (Ni,Mn,M)CO 3 ; or a mixture of Na 2 CO 3 , Li 2 CO 3 , (Ni,Mn)CO 3 and MCO 3 .
14. The process of claim 12 , wherein the pyrolyzing comprises heating the mixture of compounds at a temperature in excess of about 500° C.