Hydrogels for aqueous lithium/air battery cells
Li/air battery cells are configurable to achieve very high energy density. The cells include a protected a lithium metal or alloy anode and an aqueous catholyte in a cathode compartment. In addition to the aqueous catholyte, components of the cathode compartment include an air cathode (e.g., oxygen electrode) and a variety of other possible elements.
1. A battery cell, comprising:
a protected anode, comprising,
a lithium metal anode having a first surface and a second surface,
a protective membrane architecture on at least the first surface of the anode,
a cathode compartment comprising a cathode for reducing molecular oxygen, an aqueous catholyte, and a hydrogel reservoir structure; and,
wherein the protective membrane architecture comprises one or more materials configured to provide a first membrane surface chemically compatible with the alkali metal anode in contact with the anode, and a second membrane surface substantially impervious to and chemically compatible with the components of the cathode compartment.
2. The cell of claim 1 wherein the hydrogel structure comprises a hydrophilic polymer.
3. The cell of claim 1 wherein the hydrogel structure absorbs moisture from the ambient air during device operation.
4. The cell of claim 1 wherein the hydrogel structure comprises solid phase active salts.
5. The cell of claim 1 wherein the hydrogel structure comprises aqueous catholyte.
6. The cell of claim 1 wherein the hydrogel structure accommodates solid products of discharge.
7. The cell of claim 1 wherein the hydrogel structure retains catholyte and swells via absorption of moisture from the ambient air.
8. The cell of claim 1 wherein the hydrogel structure is or comprises a natural polymer.
9. The cell of claim 1 wherein a solid phase component of the hydrogel structure is a synthetic polymer.
10. The cell of claim 1 wherein the hydrogel structure is a physical or a chemical gel.
11. The cell of claim 1 wherein the hydrogel structure is a multicomponent hydrogel structure of two or more hydrogel compositions.
12. The cell of claim 1 wherein the hydrogel structure further comprises hydrogel contact layers having a composition different than that of the bulk hydrogel.
13. The cell of claim 1 wherein the reservoir is a hydrogel.
14. The cell of claim 1 wherein the hydrogel structure forms in-situ as water from the ambient air is absorbed into the cathode compartment.
15. The cell of claim 1 wherein the hydrogel structure retains catholyte and swells upon discharge with water molecules generated via the cell reaction.
16. The cell of claim 1 , wherein the hydrogel structure is a multi-layer, comprising a first hydrogel layer adjacent the anode and a different second hydrogel layer adjacent the cathode.
17. A method of making a battery cell comprising:
assembling the cell of claim 1 , wherein the cathode is fabricated outside of the cell prior to cell assembly.