Production of battery grade materials via an oxalate method
An active electrode material for electrochemical devices such as lithium ion batteries includes a lithium transition metal oxide which is free of sodium and sulfur contaminants. The lithium transition metal oxide is prepared by calcining a mixture of a lithium precursor and a transition metal oxalate. Electrochemical devices use such active electrodes.
1. A method of preparing a lithium transition metal oxide comprising:
preparing a first solution comprising transition metal ions;
preparing a second solution comprising oxalic acid and a precipitating agent;
adding the first solution to the second solution to form a combined solution and a precipitate of a transition metal oxalate; and
calcining a mixture of a lithium precursor and the transition metal oxalate to form the lithium transition metal oxide;
wherein:
the precipitating agent comprises ammonium hydrogen oxalate, di-ammonium oxalate, lithium oxalate, sodium oxalate, potassium oxalate, or a mixture thereof; and
the transition metal oxalate comprises a compound of formula
[M 1 α′ M 2 β′ M 3 γ′ ]C 2 O 4 ;
M 1 , M 2 , and M 3 are transition metals; and
0<α′≦1; 0<β′≦1; and 0<γ′≦1.
2. The method of claim 1 , wherein the calcining is conducted at a temperature of from about 400° C. to about 1200° C.
3. The method of claim 1 , wherein a concentration of the precipitating agent in the second solution is from about 0.5M to about 1.5M.
4. The method of claim 1 , wherein a pH of the combined solution during adding of the first solution to the second solution is below about 2.2.
5. The method of claim 1 , wherein the transition metal ions comprise at least three of Ni, Co, Mn, Fe, Cr, V, Ti, Cu, Zn, Mo, W, Zr, Nb, or Ru.
6. The method of claim 1 , wherein:
the lithium transition metal oxide comprises a compound of formula
Li x [M 1 α M 2 β M 3 γ ]O z ;
M 1 , M 2 , and M 3 are transition metals; and
0<x≦2; 0<α≦1; 0<β′≦1; 0<γ≦1; and 0<z≦3.
7. The method of claim 6 , wherein M 1 is Ni, Fe, Cu, Zn, Mg, Ca, Sr, or Ba; M 2 is Co, Cr, V, Y, La, Ce or Al; and M 3 is Mn, Ti, Zr, Nb, Mo, or Ru.
8. The method of claim 6 , wherein M 1 is Ni; M 2 is Co; and M 3 is Mn.
9. The method of claim 6 , wherein 1<x≦2; 0<α≦0.33; 0<β′≦0.5; 0<γ≦0.8; and 2<z≦3; and the sum of α, β, and γ is 1.
10. The method of claim 6 , wherein the lithium transition metal oxide exhibits a capacity of greater than 200 mAh/g in a Li coin cell.
11. The method of claim 1 , wherein the lithium precursor comprises lithium carbonate, lithium hydroxide, lithium nitrate, lithium acetate, lithium oxalate, lithium hydride, lithium oxide, lithium peroxide, lithium sulfate, or lithium fluoride.
12. A method of preparing a lithium transition metal oxide comprising:
preparing a first solution comprising transition metal ions;
preparing second solution comprising oxalic acid and a precipitating agent;
adding the first solution to the second solution to form a combined solution and a precipitate of a transition metal oxalate; and
calcining a mixture of a lithium precursor and the transition metal oxalate;
wherein:
the precipitating agent comprises ammonium hydrogen oxalate, di-ammonium oxalate, lithium oxalate, sodium oxalate, potassium oxalate, or mixture thereof;
the lithium transition metal oxide comprises a compound of formula
Li x [M 1 α M 2 β M 3 γ ]O z ;
M 1 , M 2 , and M 3 are transition metals; and
1<x≦2; 0<α≦0.33; 0≦β≦0.5; 0<γ≦0.8; and 2<z≦3; and the sum of α, β, and γ is 1; and
the transition metal oxalate comprises a compound of formula
[M 1 α′ M 2 β′ M 3 γ′ ]C 2 O 4 ; and
0<α′≦0.33; 0≦β′≦0.5; and 0<γ′≦0.8; and the sum of α′, β′, and γ′ is 1.
13. The method of claim 12 , wherein the calcining is conducted at a temperature of from about 400° C. to about 1200° C.
14. The method of claim 12 , wherein the lithium precursor comprises lithium carbonate, lithium hydroxide, lithium nitrate, lithium acetate, lithium oxalate, lithium hydride, lithium oxide, lithium peroxide, lithium sulfate, or lithium fluoride.
15. A method of preparing a lithium transition metal oxide comprising:
preparing a first solution comprising transition metal ions;
preparing a second solution comprising oxalic acid and a precipitating agent;
adding the first solution to the second solution to form a combined solution and a precipitate of a transition metal oxalate; and
calcining a mixture of a lithium precursor and the transition metal oxalate;
wherein:
the precipitating agent comprises ammonium hydrogen oxalate, di-ammonium oxalate, lithium oxalate, sodium oxalate, potassium oxalate, or mixture thereof;
the lithium transition metal oxide comprises a compound of formula
Li x [M 1 α M 2 βM 3 γ ]O z ;
M 1 , M 2 , and M 3 are transition metals; and
1<x≦2; 0<α≦0.33; 0≦β; 0<γ≦0.8; and 2<z≦3; and the sum of α and γ is 1; and
the transition metal oxalate comprises a compound of formula
[M 1 α′ M 2 β′ M 3 γ′ ]C 2 O 4 ; and
0<α′≦0.33; 0≦β′; and 0<γ′≦0.8; and the sum of α′ and γ′ is 1.
16. The method of claim 15 , wherein the calcining is conducted at a temperature of from about 400° C. to about 1200° C.
17. The method of claim 15 , wherein the lithium precursor comprises lithium carbonate, lithium hydroxide, lithium nitrate, lithium acetate, lithium oxalate, lithium hydride, lithium oxide, lithium peroxide, lithium sulfate, or lithium fluoride.