Alkaline metal-air battery cathode
A metal-air battery and a component air cathode including a solid ionically conductive polymer material.
1. A metal-air battery comprising:
an air electrode that includes: an electrically conductive material, and a solid ionically conducting polymer material;
wherein the air electrode acts to produce an hydroxide ion when the air electrode is exposed to an oxygen gas source and when the battery is under load;
wherein the solid ionically conducting polymer material ionically conducts the hydroxide ion;
wherein the solid ionically conducting polymer material is ionically conductive through the solid and not through any solvent, gel or liquid phase;
wherein the solid ionically conducting polymer material has an ionic conductivity greater than 1×10 −5 S/cm at room temperature;
wherein the solid ionically conducting polymer material has an electronic conductivity of less than 1×10 −5 S/cm at room temperature; and
wherein the solid ionically conducting polymer material has a glassy state, and wherein the solid ionically conducting polymer material conducts the hydroxide ion in the glassy state.
2. The battery of claim 1 , further comprising a negative electrode including a first electrochemically active metal; and an ionically conducting, dielectric material interposed between the air electrode and the negative electrode and in contact with the air electrode.
3. The battery of claim 1 , wherein the solid ionically conducting polymer material comprises a cationic diffusing ion, wherein the diffusivity of the cationic diffusing ion is greater than 1.0×10 −12 m 2 /S at room temperature.
4. The battery of claim 1 , wherein the solid ionically conducting polymer material comprises an anionic diffusing ion comprising the hydroxide ion, wherein the diffusivity of the anionic diffusing ion is greater than 1.0×10 −12 m 2 /S at room temperature.
5. The battery of claim 1 , wherein the solid ionically conducting polymer material comprises both an anionic diffusing ion comprising the hydroxide ion and a cationic diffusing ion, wherein each at least one cationic and anionic diffusing ion have a diffusivity, wherein the anionic diffusivity is greater than the cationic diffusivity at room temperature.
6. The battery of claim 1 , wherein the cationic transference number of the solid ionically conducting polymer material is greater than 0.5 and less than 1.0 at room temperature.
7. The battery of claim 1 , wherein the solid ionically conducting polymer material comprises lithium.
8. The battery of claim 7 , wherein the concentration of lithium is greater than 3 moles of lithium per liter of solid ionically conducting polymer material.
9. The battery of claim 1 , wherein the solid ionically conducting polymer material has an ionic conductivity greater than 1×10 −4 S/cm at room temperature.
10. The battery of claim 1 , wherein the solid ionically conducting polymer material has an ionic conductivity greater than 1×10 −3 S/cm at 80° C.
11. The battery of claim 1 , wherein the solid ionically conducting polymer material has an ionic conductivity greater than 1×10 −5 S/cm at 40° C.
12. The battery of claim 1 , wherein the solid ionically conducting polymer material comprises both an anionic diffusing comprising the hydroxide ion and a cationic diffusing ion, wherein the cationic diffusing ion comprises lithium, and wherein the diffusivity of lithium ion and the hydroxide ion are both greater than 1.0×10 −13 m 2 /s at room temperature.
13. The battery of claim 1 , wherein the solid ionically conducting polymer material exhibits UL 94 V-0 flame retardancy.
14. The battery of claim 1 , wherein the solid ionically conducting polymer material is formed from the reaction product of a base polymer, electron acceptor and an ionic compound.
15. The battery of claim 14 , wherein the base polymer is polyphenylene sulfide (PPS) or a liquid crystal polymer.
16. The battery of claim 1 , wherein the air electrode further comprises a metal oxide.
17. The battery of claim 16 , wherein the metal oxide is manganese dioxide.
18. The battery of claim 1 wherein the air electrode further comprises manganese dioxide, and the manganese dioxide is selected from a group comprising β-MnO2 (pyrolusite), ramsdellite, γ-MnO2, ε-MnO2, λ-MnO2, EMD, CMD, and combinations thereof.
19. The battery of claim 2 , wherein the first electrochemically active metal comprises zinc, aluminum, calcium, magnesium, potassium, sodium or lithium.