Protected lithium electrodes based on sintered ceramic or glass ceramic membranes
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 handle-able composite protective membrane on the first surface of the electrode and having a gap-free interface therewith, the composite protective 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, the membrane comprising a substantially impervious sintered ceramic or glass-ceramic layer having a thickness between 10 and 1000 microns;
wherein the ionic conductivity of the membrane is at least 10 −7 S/cm; a current collector on the second surface of the active metal electrode; and
wherein the device component can be handled or stored in normal ambient atmospheric conditions without degradation prior to incorporation into an electrochemical device.
2. The component of claim 1 , wherein the active metal of the electrode is lithium.
3. The component of claim 1 , wherein the electrode comprises evaporated lithium metal.
4. The component of claim 3 , wherein the thickness of the substantially impervious layer is between 10 and 100 microns.
5. The component of claim 1 , wherein the composite protective membrane comprises,
a first material in contact with the active metal electrode, the first material being conductive to ions of the active metal and chemically compatible with the active metal; and
a second material in contact with the first material, the second material being substantially impervious, conductive to ions of the active metal and chemically compatible with the first material and the active metal corrosive environments;
wherein the ionic conductivity of the composite is at least 10 −5 S/cm.
6. The component of claim 5 , wherein the protective membrane is a bi-functionally compatible composite, the composite comprising:
an active metal ion conductive first material layer, the layer chemically compatible and in direct contact with the active metal electrode; and
an active metal ion conductive second material layer in contact with the first material layer, the second material layer substantially impervious and chemically compatible with both the first material layer and the active metal electrode corrosive environments.
7. The component of claim 6 , wherein the second material layer is a substantially impervious glass-ceramic layer.
8. The component of claim 7 , wherein the second material layer is a substantially impervious sintered ceramic.
9. The component of claim 6 , wherein the second material layer has 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 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.