Ionically conductive membranes for protection of active metal anodes and battery cells
Disclosed are ionically conductive membranes for protection of active metal anodes and methods for their fabrication. The membranes may be incorporated in active metal negative electrode (anode) structures and battery cells. In accordance with the invention, the membrane has the desired properties of high overall ionic conductivity and chemical stability towards the anode, the cathode and ambient conditions encountered in battery manufacturing. The membrane is capable of protecting an active metal anode from deleterious reaction with other battery components or ambient conditions while providing a high level of ionic conductivity to facilitate manufacture and/or enhance performance of a battery cell in which the membrane is incorporated.
1. An electrochemical device component, comprising:
an active metal electrode having a first surface and a second surface; and
a protective membrane on the first surface of the electrode and having a smooth gap-free interface therewith, the membrane being ionically conductive and chemically compatible with the active metal on a side in contact with the active metal electrode, and substantially impervious, ionically conductive and chemically compatible with active metal corrosive environments on the other side;
wherein the ionic conductivity of the membrane is at least 10 −5 S/cm; and
wherein the protective membrane comprises a composite, the composite comprising,
a first material in contact with the electrode, the first material being ionically conductive and chemically compatible with the active metal, wherein the first material comprises a composite reaction product of Li with Cu 3 N, and
a second material in contact with the first material, the second material being substantially impervious, ionically conductive and chemically compatible with the first material and active metal corrosive environments, the second material selected from the group consisting of glassy or amorphous metal ion conductors, ceramic active metal ion conductors, and glass-ceramic active metal ion conductors,
wherein the ionic conductivity of the composite is at least 10 −5 S/cm.
2. The component of claim 1 , wherein the thickness of the second material in the composite is about 10 to 1000 microns.
3. The component of claim 1 , further comprising a current collector on the second surface of the active metal electrode.
4. The component of claim 1 , wherein the ionic conductivity of the membrane is at least 10 −4 S/cm.
5. The component of claim 1 , wherein the active metal of the electrode is lithium or a lithium alloy.
6. The component of claim 1 , wherein the second material comprises a glass-ceramic active metal ion conductor.
7. The component of claim 1 , wherein the second material is an ion conductive glass-ceramic having the following composition:
Composition
mol %
P 2 O 5
26-55%
SiO 2
0-15%
GeO 2 + TiO 2
25-50%
in which GeO 2
0-50%
TiO 2
0-50%
ZrO 2
0-10%
M 2 O 3
0 < 10%
Al 2 O 3
0-15%
Ga 2 O 3
0-15%
Li 2 O
3-25%
and containing a predominant crystalline phase composed of Li 1+x (M,Al,Ga) x (Ge 1−y Ti y ) 2−x (PO 4 ) 3 where X≦0.8 and 0≦Y≦1.0, and where M is an element selected from the group consisting of Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm and Yb and/or and Li 1+x+y Q x Ti 2−x Si y P 3−y O 12 where 0<X≦0.4 and 0<Y≦0.6, and where Q is Al or Ga.
8. The component of claim 1 , wherein the second material is a flexible membrane comprising particles of an ion conductive glass-ceramic having the following composition:
Composition
mol %
P 2 O 5
26-55%
SiO 2
0-15%
GeO 2 + TiO 2
25-50%
in which GeO 2
0-50%
TiO 2
0-50%
ZrO 2
0-10%
M 2 O 3
0 < 10%
Al 2 O 3
0-15%
Ga 2 O 3
0-15%
Li 2 O
3-25%
and containing a predominant crystalline phase composed of Li 1+x (M,Al,Ga) x (Ge 1−y Ti y ) 2−x (PO 4 ) 3 where X≦0.8 and 0≦Y≦1.0, and where M is an element selected from the group consisting of Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm and Yb and/or and Li 1+x+Y Q x Ti 2−x Si y P 3−y O 12 where 0<X≦0.4 and 0<Y≦0.6, and where Q is Al or Ga in a solid polymer electrolyte.
9. The component of claim 1 , wherein the protective composite is a laminate of discrete layers of the first material and the second material.
10. The component of claim 1 , wherein the protective composite comprises a gradual transition between the first material and the second material.
11. An electrochemical device component, comprising:
an active metal electrode having a first surface and a second surface; and
a protective membrane on the first surface of the electrode and having a smooth gap-free interface therewith, the membrane being ionically conductive and chemically compatible with the active metal on a side in contact with the active metal electrode, and substantially impervious, ionically conductive and chemically compatible with active metal conosive environments on the other side;
wherein the ionic conductivity of the membrane is at least 10 −5 S/cm; and
wherein the protective membrane comprises a composite, the composite comprising,
a first material in contact with the electrode, the first material being ionically conductive and chemically compatible with the active metal, wherein the first material comprises a composite reaction product of the active metal with copper nitride (Cu 3 N), and
a second material in contact with the first material, the second material being substantially impervious, ionically conductive and chemically compatible with the first material and active metal corrosive environments, the second material selected from the group consisting of glassy or amorphous metal ion conductors, ceramic active metal ion conductors, and glass-ceramic active metal ion conductors,
wherein the ionic conductivity of the composite is at least 10 −5 S/cm.