Pre-lithiated electrode materials and cells employing the same
Provided are compositions, systems, and methods of making and using pre-lithiated cathodes for use in lithium ion secondary cells as the means of supplying extra lithium to the cell. The chemically or electrochemically pre-lithiated cathodes include cathode active material that is pre-lithiated prior to assembly into an electrochemical cell. The process of producing pre-lithiated cathodes includes contacting a cathode active material to an electrolyte, the electrolyte further contacting a counter electrode lithium source and applying an electric potential or current to the cathode active material and the lithium source thereby pre-lithiating the cathode active material with lithium. An electrochemical cell is also provided including the pre-lithiated cathode, an anode, a separator and an electrolyte.
1. A chemically or electrochemically pre-lithiated cathode for use in an electrochemical cell comprising:
a pre-lithiated cathode active material wherein the cathode active material comprises the chemical formula: Li 1+a M x O y and is made by chemically or electrochemically pre-lithiating an as synthesized lithium containing cathode active material prior to assembly into an electrochemical cell, where
0<a≤1,
0<x,
2≤y≤6, and
M is one or more elements selected from the group consisting of one or more transition metals, Al, B, Mg, and combinations thereof.
2. The chemically or electrochemically pre-lithiated cathode of claim 1 wherein 0.02<a≤1.
3. The chemically or electrochemically pre-lithiated cathode of claim 1 wherein the pre-lithiated cathode active material comprises the chemical formula:
Li 1+a Ni x Co y Mn z O 2 , where,
0<a≤1,
0≤x≤1,
0≤y≤1,
0≤z≤1, and wherein at least one of x, y, or z is non-zero.
4. The chemically or electrochemically pre-lithiated cathode of claim 1 wherein the pre-lithiated cathode has a substantially spinel structure.
5. The chemically or electrochemically pre-lithiated cathode of claim 1 wherein the pre-lithiated cathode has a substantially layered structure.
6. The chemically or electrochemically pre-lithiated cathode of claim 5 wherein the layered structure is an α-NaFeO 2 structure.
7. The chemically or electrochemically pre-lithiated cathode of claim 1 wherein the cathode active material is described by the general formula: Li 1+a D v Ni x Co y Mn z A w O 2 where,
0<a≤1,
0≤x≤1,
0≤y≤1,
0≤z≤1,
0≤w≤0.15,
0≤v≤0.10, where at least one of x, y, or z is non-zero,
A is one or more elements selected from the group comprising Sc, Ti, V, Cr, Fe, Cu, Zn, Al, Ga, Ge, As, B, and Mg, and
D is one or more elements selected from the group consisting Be, Na, Mg, K, Ca, Sr, Ni, Co, Mn, Sc, Ti, V, Cr, Fe, Cu, Zn, Al, Ga, Ge, B, and As.
8. The chemically or electrochemically pre-lithiated cathode of claim 7 wherein the cathode active material has a gradient in Co, Mn, or both.
9. The chemically or electrochemically pre-lithiated cathode of claim 1 wherein a thermodynamic potential of the pre-lithiated cathode is less than 3.0 V versus Li.
10. An electrochemical cell comprising:
the chemically or electrochemically pre-lithiated cathode of claim 1 ,
an anode,
a separator, and
a lithium-ion conducting electrolyte.
11. A process of producing the pre-lithiated cathode of claim 1 comprising:
contacting a cathode active material to an electrolyte, the electrolyte further contacting a counter electrode lithium source; and
applying an electric potential or current to the cathode active material and the lithium source to increase the lithium content of the cathode active material thereby pre-lithiating the cathode active material with lithium.
12. The process of claim 11 wherein step of contacting is performed by a reel-to-reel process comprising drawing a web of cathode active material coated onto a conducting substrate through an electrolyte bath at a pre-lithiation speed.
13. The process of claim 11 wherein the lithium source is selected from the group consisting of spinels, olivines, silicates, Li 2 MnO 3 , or Li metal.
14. The process of claim 11 wherein a current density of the step of applying is 0.2-20 mA/cm 2 , optionally 10 mA/cm 2 .
15. The process of claim 11 further comprising rinsing the pre-lithiated cathode active material.
16. The process of claim 11 further comprising drying the pre-lithiated cathode active material.
17. The process of claim 11 wherein the pre-lithiated cathode is characterized by a first charge capacity greater than a control otherwise identical non-prelithiated cathode.
18. The process of claim 17 wherein the first charge capacity is 10 mAh/g or greater relative to the control.
19. The process of claim 11
i) wherein the pre-lithiated cathode comprises the chemical formula: Li 1+a Ni x Co y Mn z O 2 , where,
0<a≤1,
0≤x≤1,
0≤y≤1, and
0≤z≤1 wherein at least one of x, y, or z is non-zero; or
ii) wherein the cathode active material comprises the general formula: Li 1+a D v Ni x Co y Mn z A w O 2 , where,
0<a≤1,
0≤x≤1,
0≤y≤1,
0≤z≤1,
0≤w≤0.15,
0≤v≤0.10, where at least one of x, y, or z is non-zero,
A is one or more elements selected from the group comprising Sc, Ti, V, Cr, Fe, Cu, Zn, Al, Ga, Ge, As, B and Mg, and
D is one or more elements selected from the group consisting Be, Na, Mg, K, Ca, Sr, Ni, Co, Mn, Sc, Ti, V, Cr, Fe, Cu, Zn, Al, Ga, Ge, B and As.
20. The process of claim 19 wherein 0.02<a≤1, optionally wherein 0.5<a≤1.
21. The process of claim 19 wherein the cathode active material comprises the general formula: Li 1+a D v Ni x Co y Mn z A w O 2 , where,
0<a≤1,
0≤x≤1,
0≤y≤1,
0≤z≤1,
0≤w≤0.15,
0≤v≤0.10, where at least one of x, y, or z is non-zero,
A is one or more elements selected from the group comprising Sc, Ti, V, Cr, Fe, Cu, Zn, Al, Ga, Ge, As, B and Mg, and
D is one or more elements selected from the group consisting Be, Na, Mg, K, Ca, Sr, Ni, Co, Mn, Sc, Ti, V, Cr, Fe, Cu, Zn, Al, Ga, Ge, B and As, and
wherein the cathode active material has a gradient in Co, Mn, or both.