Treating sulfide glass surfaces and making solid state laminate electrode assemblies
Methods for making solid-state laminate electrode assemblies include methods of forming a solid electrolyte interphase (SEI) by ion implanting nitrogen and/or phosphorous into the glass surface by ion implantation.
1. A method for making a solid-state laminate electrode assembly, the method comprising:
i) providing a lithium ion conducting sulfide glass substrate, the substrate comprising a sulfide glass solid electrolyte sheet having room temperature Li ion conductivity of at least 10 −5 S/cm, the sulfide glass substrate having first and second major surfaces;
ii) injecting nitrogen and/or phosphorous into the first surface of the sulfide glass substrate, wherein the nitrogen and/or phosphorous penetrates the glass surface forming an implanted zone; and
iii) evaporating lithium metal onto the implanted zone of the sulfide glass substrate; wherein at least a portion of the evaporated lithium reacts with the injected nitrogen and/or phosphorous to form a solid electrolyte interphase (SEI) layer comprising lithium and one or both of nitrogen and phosphorous.
2. The method of claim 1 , wherein the implanted zone is substantially uniform and the SEI layer is continuous.
3. The method of claim 1 , wherein the SEI comprises lithium nitride.
4. The method of claim 1 , wherein the SEI comprises lithium phosphide.
5. The method of claim 1 , wherein the SEI is a continuous layer of a lithium nitride and/or lithium phosphide compound.
6. The method of claim 1 , wherein the injecting is performed by ion implantation using a nitrogen and/or phosphorous ion gun.
7. The method of claim 1 , wherein the nitrogen and/or phosphorous ion implantation zone is not greater than 10 nm deep.
8. The method of claim 1 , wherein the nitrogen and/or phosphorous ion implantation zone is not greater than 10-100 nm deep.
9. The method of claim 1 , wherein the nitrogen and/or phosphorous ion implantation zone is not greater than 100-1000 nm deep.
10. The method of claim 1 , wherein the injecting and the lithium evaporation takes place simultaneously.
11. The method of claim 10 , comprising injecting nitrogen and/or phosphorous onto the glass surface prior to lithium evaporation; simultaneously injecting and evaporating lithium metal; and, stopping the nitrogen injection while continuing the evaporation.