BINARY PHOSPHORUS NITRIDE PROTECTIVE SOLID ELECTROLYTE INTERMEDIARY STRUCTURES FOR ELECTRODE ASSEMBLIES
An intermediary solid electrolyte structure having a Li ion conducting solid electrolyte layer with a thin phosphorus nitride film covering provides protection of the solid electrolyte surfaces against reaction with moisture during sulfide glass solid electrolyte storage, transportation, and cell assembly in a dry room atmosphere.
1 . An intermediary solid electrolyte structure comprising a Li ion conducting solid electrolyte layer having a first major surface and a thin phosphorus nitride film covering the first major surface.
2 . The intermediary solid electrolyte structure of claim 1 wherein the phosphorus nitride film has stoichiometry of P3N5.
3 . The intermediary solid electrolyte structure of claim 2 wherein the solid electrolyte layer is a sulfide-based Li ion conductor.
4 . The intermediary solid electrolyte structure of claim 3 wherein the sulfide-based Li ion conductor is a glass.
5 . The intermediary solid electrolyte structure of claim 2 wherein the solid electrolyte layer is an oxide-based or phosphate-based Li ion conductor.
6 . The intermediary solid electrolyte structure of claim 5 wherein the oxide-based Li ion conductor is of the garnet type.
7 . The intermediary solid electrolyte structure of claim 1 wherein the thin phosphorus nitride film is lithiated.
8 . The intermediary solid electrolyte structure of claim 1 , wherein the thickness of the thin phosphorus nitride film is about 10 nm.
9 . The intermediary solid electrolyte structure of claim 7 , wherein the thickness of the thin phosphorus nitride film is about 10 nm.
10 . The intermediary solid electrolyte structure of claim 1 , wherein the thickness of the thin phosphorus nitride film is about 20 nm.
11 . The intermediary solid electrolyte structure of claim 7 , wherein the thickness of the thin phosphorus nitride film is about 20 nm.
12 . A lithium metal electrode assembly comprising the intermediary solid electrolyte structure of claim 1 and further comprising a thin layer of lithium metal covering the phosphorus nitride film.
13 . The lithium metal electrode assembly of claim 12 wherein the lithium metal layer has a thickness of about 2 um.
14 . The lithium metal electrode assembly of claim 12 wherein the lithium metal layer has a thickness of about 5 um.
15 . A method of making an intermediary solid electrolyte structure comprising the steps of providing a solid electrolyte layer and physical vapor depositing a thin film of phosphorus nitride (PxNy) onto a first major surface of the solid electrolyte layer.
16 . The method of claim 15 wherein the thickness of the thin phosphorus nitride film is about 20 nm.
17 . The method of claim 16 wherein the solid electrolyte layer is a sulfide-based Li ion conductor.
18 . The method of claim 16 wherein the solid electrolyte layer is an oxide-based or phosphate-based Li ion conductor.
19 . The method of claim 18 wherein the solid electrolyte layer is of the garnet type.
20 . The method of claim 15 further comprising the step of evaporating lithium metal onto the phosphorus nitride film.
21 . The method of claim 20 wherein the lithium evaporating step lithiates or converts the phosphorus nitride layer into a lithiated phosphorus nitride film.
22 . The method of claim 15 wherein the stoichiometry of the phosphorus nitride is P 3 N 5 .