Protective layers for electrochemical cells
Articles and methods including layers for protection of electrodes in electrochemical cells are provided. As described herein, a layer, such as a protective layer for an electrode, may comprise a plurality of particles (e.g., crystalline inorganic particles, amorphous inorganic particles). In some embodiments, at least a portion of the plurality of particles (e.g., inorganic particles) are fused to one another. For instance, in some embodiments, the layer may be formed by aerosol deposition or another suitable process that involves subjecting the particles to a relatively high velocity such that fusion of particles occurs during deposition. In some embodiments, the layer (e.g., the layer comprising a plurality of particles) is an ion-conducting layer.
1. A method of forming an article for use in an electrochemical cell, the method comprising:
exposing a first layer comprising a first material to a plurality of particles having a velocity of at least 200 m/s, wherein the particles comprise a second material different from the first material;
embedding at least a portion of the particles in the first layer; and
forming a second layer comprising the plurality of particles, wherein at least a portion of the plurality of particles are fused to one another,
wherein the exposing step is performed at a pressure of greater than or equal to 0.5 mTorr and less than or equal to 100 mTorr,
wherein at least a first portion of the plurality of particles comprise an ionically-conductive material and at least a second portion of the plurality of particles comprise a non-ionically conductive material, and
wherein the second layer has an ionic conductivity between about 10 −6 S/cm and about 10 −2 S/cm.
2. A method of forming an article for use in an electrochemical cell, the method comprising:
exposing a first layer comprising a first material to a plurality of particles having a velocity sufficient to cause fusion of at least some of the particles, wherein the particles comprise a second material;
embedding at least a portion of the particles in the first layer; and
forming a second layer comprising the second material,
wherein the exposing step is performed at a pressure of greater than or equal to 0.5 mTorr and less than or equal to 100 mTorr,
wherein the second layer has an ionic conductivity between about 10 −6 S/cm and about 10 −2 S/cm.
3. A The method of claim 2 , comprising fusing at least a portion of the plurality of particles when forming the second layer.
4. The method of claim 2 , comprising forming a continuous, ionically conductive pathway from the plurality of particles.
5. The method of claim 2 , wherein exposing the first layer to the plurality of particles comprises spraying the plurality of particles onto the first layer using aerosol deposition.
6. The method of claim 2 , wherein the exposing step is performed at a temperature of less than 500° C.
7. A The method of claim 2 , comprising exposing the first layer to the plurality of particles having a velocity of at least 500 m/s, and up to 2000 m/s.
8. The method of claim 2 , wherein at least 10 vol % of the second layer comprises one or more continuous pathways.
9. The method of claim 2 , wherein the second layer has an ionic conductivity between about 10-5 S/cm and about 10-3 S/cm.
10. The method of claim 2 , wherein the second layer has an average thickness between about 3 microns and about 25 microns.
11. The method of claim 2 , wherein the plurality of particles have an average largest cross-sectional dimension of between about 0.5 microns and about 20 microns.
12. The method of claim 2 wherein at least 50% of the plurality of particles are fused to one another in the second layer.
13. The method of claim 2 , wherein the second layer comprises an ionically-conductive material and a non-conically conductive material.
14. The method of claim 2 , wherein the second layer comprises an ionically-conductive material and a non-ionically conductive material; and wherein a weight ratio of the ionically conductive material to the non-ionically conductive material is at least 80:20.
15. The method of claim 2 , wherein the ionically-conductive material comprises an inorganic material.
16. The method of claim 2 , wherein the ionically-conductive material comprises a ceramic, wherein the ceramic is a garnet.
17. The method of claim 2 , wherein the ionically conductive material is between 1% and 99% crystalline.
18. The method of claim 2 , wherein the ionically conductive material has a Young's elastic modulus of at least 1 GPa.
19. The method of claim 2 , wherein the second layer comprises an ionically-conductive material and a non-ionically conductive material, and wherein the non-ionically conductive material has a Young's elastic modulus of at least 2 times smaller than the modulus of ionically conductive material.
20. The method of claim 13 , wherein the non-ionically conductive material comprises a polymer.
21. The method of claim 13 , wherein the non-ionically conductive material comprises an inorganic material.
22. The method of claim 2 , wherein the second layer has a density of between 1.5 and 6 g/cm 3 .
23. The method of claim 2 , wherein the second layer has a porosity of less than about 5%.
24. The method of claim 2 , wherein the first layer comprises a polymer.
25. The method of claim 24 , wherein the polymer is a polymer gel or forms polymer gel when exposed to liquid electrolyte.
26. The method of claim 2 , wherein the first layer comprises lithium metal.
27. The method of claim 2 , wherein the first layer is a separator.
28. The method of claim 2 , wherein the first layer is porous.
29. The method of claim 2 , wherein the first layer is non-porous.
30. The method of claim 2 , comprising exposing the second layer to a liquid electrolyte.