Buffered negative electrode-electrolyte assembly, battery, and method of manufacture thereof
A buffered negative electrode-electrolyte assembly includes: a porous negative electrode comprising a metal, a transition metal nitride, or a combination thereof; a solid-state electrolyte; and a buffer layer between the porous negative electrode and the solid-state electrolyte. The buffer layer comprising a buffer composition according to Formula (1) M m N n Z z H h X x . The buffer composition has an electronic conductivity that is less than or equal to 1×10 −2 times an electronic conductivity of the solid-state electrolyte, and the buffer composition has an ionic conductivity less than or equal to 1×10 −6 times an ionic conductivity of the solid-state electrolyte.
1. A buffered negative electrode-electrolyte assembly comprising:
a porous negative electrode comprising a metal, a transition metal nitride, or a combination thereof;
a solid-state electrolyte; and
a buffer layer between the porous negative electrode and the solid-state electrolyte, the buffer layer comprising a buffer composition according to Formula (1)
M n N n Z z H h X x (1)
wherein
M is Na, K, Rb, Cs, Al, or a metal of Group 2 or 3, or a combination thereof, wherein m is 1, 2, 3, or 4,
X is at least one halogen and wherein x is 0, 1, 2, or 6,
Z is 0, S, or a combination thereof, and z is 0, 1, 2, 3, or 4,
n is 0, 1, or 2, and
h is 0, 1, 2, or 3,
provided that x+z+n+h is at least 1, and
wherein the buffer composition has an electronic conductivity that is less than or equal to 1×10 −2 times an electronic conductivity of the solid-state electrolyte, and the buffer composition has an ionic conductivity less than or equal to 1×10 −6 times an ionic conductivity of the solid-state electrolyte.
2. The assembly of claim 1 , wherein the buffer composition has a bandgap greater than 3 electron-volts.
3. The assembly of claim 1 , wherein the buffer composition comprises a binary compound.
4. The assembly of claim 1 , wherein M in Formula (1) is K, Rb, Cs, Be, Ca, Sr, Ba, Sc, Y, Th, Al, Lu, Tm, Er, Ho, Dy, Tb, Sm, Nd, Pr, La, Yb, La, or Yb.
5. The assembly of claim 1 , wherein the buffer composition comprises at least one of BeO, SrF 2 , KCl, CsCl, RbCl, SrBr 2 , ThO 2 , CsBr, RbBr, Y 2 O 3 , AlN, Lu 2 O 3 , Tm 2 O 3 , Ba 4 I 6 O, Er 2 O 3 , Ho 2 O 3 , Dy 2 O 3 , Tb 2 O 3 , CSI, KI, Sm 2 O 3 , Sm 2 O 2 S, RbI, Nd 2 O 3 , Pr 2 O 3 , CaO, La 2 O 3 , YbO, BaI 2 , Be 3 N 2 , La 2 SO 2 , YbF 2 , CaH 2 , SrBe 3 O 4 , or Pr 2 SO 2 .
6. The assembly of claim 1 , wherein the buffer layer has a thickness of 5 to 50 nm.
7. The assembly of claim 1 , wherein the buffer layer is a conformal coating on a surface of the porous negative electrode.
8. The assembly of claim 1 , wherein the buffer layer is on a portion of a surface of the porous negative electrode.
9. The assembly of claim 1 , wherein a portion of the solid-state electrolyte is directly exposed to a pore of the porous negative electrode.
10. The assembly of claim 1 , wherein the porous negative electrode has an average pore diameter between 25 nm and 400 nm and a wall thickness of 5 nm to 100 nm.
11. The assembly of claim 1 , wherein the porous negative electrode has a porosity of 60% to 75%.
12. The assembly of claim 1 , wherein the porous negative electrode comprises the transition metal nitride.
13. The assembly of claim 1 , wherein the solid-state electrolyte comprises an organic solid electrolyte, an oxide-containing inorganic solid electrolyte, a sulfide-containing inorganic solid electrolyte, or a combination thereof.
14. An electrochemical cell comprising:
a positive electrode; and
the buffered negative electrode-electrolyte assembly of claim 1 on the positive electrode.
15. The electrochemical cell of claim 14 , wherein the positive electrode comprises a lithium transition metal oxide, a lithium transition metal phosphate, or a combination thereof.
16. A method of manufacturing a electrochemical cell, the method comprising:
disposing a buffer layer between a solid-state electrolyte and a porous negative electrode, the porous negative electrode comprising a metal, a transition metal nitride, or a combination thereof, to form a buffered negative electrode-electrolyte assembly; and
disposing a positive electrode on the solid-state electrolyte to manufacture the electrochemical cell,
wherein the buffer layer comprises a buffer composition according to Formula (1)
M n N n Z z H h X x (1)
wherein
M is Na, K, Rb, Cs, Al, a metal of Group 2 or 3, or a combination thereof, wherein m is 1, 2, 3, or 4,
X is at least one halogen and wherein x is 0, 1, 2, or 6,
Z is 0, S, or a combination thereof, and z is 0, 1, 2, 3, or 4,
n is 0, 1, or 2, and
h is 0, 1, 2, or 3,
provided that x+z+n+h is at least 1, and
wherein
the buffer composition has an electronic conductivity that is 1×10 −8 to 1×10 −2 times an electronic conductivity of the solid-state electrolyte, and
the buffer composition has an ionic conductivity less than or equal to 1×10 −6 times an ionic conductivity of the solid-state electrolyte.
17. The assembly of claim 1 , wherein when M is Sr, z+n+h is at least 1, and when M is Al or Y, x+n+h is at least 1.
18. The assembly of claim 1 , wherein M in Formula (1) is K, Rb, Cs, Be, Ca, Ba, Sc, Th, Lu, Tm, Er, Ho, Dy, Tb, Sm, Nd, Pr, La, La, or Yb.
19. The assembly of claim 1 , wherein M in Formula (1) is Eu, Ho, Dy, or Lu.
20. The assembly of claim 1 , wherein the buffer composition comprises at least one of BeO, KCl, CsCl, RbCl, SrBr 2 , ThO 2 , CsBr, RbBr, AlN, Lu 2 O 3 , Tm 2 O 3 , Ba 4 I 6 O, Er 2 O 3 , Ho 2 O 3 , Dy 2 O 3 , Tb 2 O 3 , CSI, KI, Sm 2 O 3 , Sm 2 O 2 S, RbI, Nd 2 O 3 , Pr 2 O 3 , CaO, La 2 O 3 , YbO, BaI 2 , Be 3 N 2 , La 2 SO 2 , YbF 2 , CaH 2 , SrBe 3 O 4 , or Pr 2 SO 2 .