Protective layers in lithium-ion electrochemical cells and associated electrodes and methods
Protective layers in lithium-ion electrochemical cells, and associated electrodes and methods, are generally described. The protective layers may comprise lithium-ion-conductive inorganic ceramic materials, such as lithium oxide, lithium nitride, and/or lithium oxysulfide. The resulting lithium-ion electrochemical cells may exhibit enhanced performance, including reduced capacity fade rates and reduced self-discharge rates.
1. An electrochemical cell, comprising:
a first electrode, wherein the first electrode is a lithium intercalation electrode, and wherein the first electrode comprises:
a layer comprising a first electroactive material, wherein the first electroactive material is a lithium intercalation compound; and
an inorganic lithium-ion-conductive layer disposed on a surface of the layer comprising the first electroactive material, wherein the inorganic lithium-ion-conductive layer has a porosity of at least 1% by volume and less than 30% by volume, wherein the inorganic lithium-ion-conductive layer comprises an amorphous inorganic material, wherein the inorganic lithium-ion conductive layer is integrated with the first electroactive material, and wherein the inorganic lithium-ion-conductive layer comprises columnar particles;
a liquid electrolyte, wherein the liquid electrolyte is an organic electrolyte; and
a second electrode,
wherein the inorganic lithium-ion-conductive layer is configured to substantially inhibit transport of a species between the first electrode and the second electrode, and wherein the species comprises a species decomposed from the first electrode and/or a species decomposed from the electrolyte.
2. A method of fabricating an electrochemical cell, comprising:
depositing an inorganic lithium-ion-conductive layer on a layer comprising a first electroactive material to form a first electrode, wherein the first electroactive material is a lithium intercalation compound, wherein the inorganic lithium-ion-conductive layer has a porosity of at least 1% by volume and less than 30% by volume, wherein the inorganic lithium-ion-conductive layer comprises an amorphous inorganic material, wherein the inorganic lithium-ion conductive layer is integrated with the first electroactive material, and wherein the inorganic lithium-ion-conductive layer comprises columnar particles; and
assembling the first electrode with a liquid electrolyte and a second electrode,
wherein the liquid electrolyte is an organic electrolyte, wherein the inorganic lithium-ion-conductive layer is configured to substantially inhibit transport of a species between the first electrode and the second electrode, and wherein the species comprises a species decomposed from the first electrode and/or a species decomposed from the electrolyte.
3. The electrochemical cell of claim 1 , wherein at least a portion of the first electroactive material is in direct contact with the liquid electrolyte.
4. The method of claim 2 , wherein at least a portion of the first electroactive material is in direct contact with the liquid electrolyte.
5. The electrochemical cell of claim 1 , wherein:
the inorganic lithium-ion-conductive layer comprises lithium; and
at least a portion of the first electrode is in contact with the electrolyte.
6. A method, comprising:
cycling the electrochemical cell of claim 1 , wherein the inorganic lithium-ion-conductive layer comprises lithium; and
substantially inhibiting the species decomposed from the first electrode and/or the species decomposed from the electrolyte from residing at the second electrode.
7. The electrochemical cell of claim 1 , wherein the inorganic lithium-ion-conductive layer has a thickness of at least 0.1 microns and at most 10 microns.
8. The electrochemical cell of claim 1 , wherein the layer comprising the first electroactive material comprises a plurality of particles of the first electroactive material.
9. The electrochemical cell of claim 8 , wherein at least a portion of the plurality of particles of the first electroactive material have a coating.
10. The electrochemical cell of claim 1 , wherein the inorganic lithium-ion-conductive layer comprises a ceramic material.
11. The electrochemical cell of claim 10 , wherein the ceramic material comprises lithium oxide, lithium nitride, lithium oxysulfide, Li 10 GeP 2 S 12 , and/or Li 7 La 3 Zr 2 O 12 .
12. The electrochemical cell of claim 1 , wherein the inorganic lithium-ion-conductive layer has a surface roughness Rz of between 10 nm and 20 μm.
13. The electrochemical cell of claim 8 , wherein the plurality of particles of the layer comprising the first electroactive material has a mean maximum cross-sectional dimension of between 1 nm and 15 μm.
14. The electrochemical cell of claim 1 , wherein the layer comprising the first electroactive material has a porosity at least 10% by volume and less than 70% by volume.
15. The electrochemical cell of claim 1 , wherein the first electrode is a cathode.
16. The electrochemical cell of claim 1 , wherein the first electroactive material is a layered oxide, a transition metal polyanion oxide, and/or a spinel.
17. The electrochemical cell of claim 1 , wherein the first electroactive material is lithium titanate, lithium cobalt oxide, lithium iron phosphate, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt aluminum oxide, and/or lithium nickel cobalt manganese oxide.
18. The electrochemical cell of claim 1 , wherein the porosity of the inorganic lithium-ion-conductive layer is greater than or equal to 10% by volume and less than 30% by volume.
19. The electrochemical cell of claim 1 , wherein the electrochemical cell further comprises a separator.
20. The electrochemical cell of claim 1 , wherein the inorganic lithium-ion-conductive layer is a unitary material.
21. The electrochemical cell of claim 1 , wherein the porosity of the inorganic lithium-ion-conductive layer is less than 5% by volume.