Solid-state battery

A solid-state electrochemical cell (SSEC), comprising:

• (a) a positive electrode layer comprising an active material and a sulfide catholyte, wherein the active material is selected from LiNixMnyCozO2, and LiNixAlyCozO2, wherein x+y+z is equal to 1;
• (b) a single ion conducting, solid-state buffer layer, wherein the single ion conducting, solid-state buffer layer comprises a sulfide;
• (c) a borohydride bonding layer comprising:
• A·(LiBH4)·B·(LiX)·C·(LiNH2),
• wherein X is fluorine, bromine, chlorine, iodine, or a combination thereof, and
• wherein 3≤A≤6, 2≤B≤5, and 0≤C≤9;
• and
• (d) a lithium-stuffed garnet layer, wherein the lithium-stuffed garnet layer comprises a lithium-stuffed garnet selected from LiALaBM′CM″DZrEOF, LiALaBM′CM″DTaEOF, or LiALaBM′CM″DNbEOF, wherein 4<A<8.5, 1.5<B<4, 0≤C≤2, 0≤D≤2;
• 0≤E≤3, 10≤F≤13, and M′ and M″ are each, independently in each instance selected from Ga, Al, Mo, W, Nb, Sb, Ca, Ba, Sr, Ce, Hf, Rb, and Ta, or LiaLabZrcAldMe″eOf, wherein 5<a<8.5;
• 2<b<4;
• 0<c≤2.5;
• 0≤d<2;
• 0≤e<2, and 10<f<13 and Me″ is a metal selected from Ga, Nb, Ta, V, W, Mo, and Sb;
• wherein the buffer layer is a layer in contact with the positive electrode layer;
• and
• wherein the borohydride bonding layer is between and in contact with the lithium-stuffed garnet layer and the buffer layer in contact with the positive electrode.

A dual layer stack comprising:

• (a) a positive electrode layer comprising an active material and a sulfide catholyte, wherein the active material is selected from LiNixMnyCozO2, and LiNixAlyCozO2, wherein x+y+z is equal to 1;
• and
• (b) a single ion conducting, solid-state buffer layer, wherein the single ion conducting, solid-state buffer layer comprises a sulfide;
• wherein the buffer layer has a thickness of 1 μm to 15 μm;
• and
• wherein the buffer layer is a layer in contact with the positive electrode layer.