Magnesium metal devices and methods of making the same
The present disclosure relates to a device that includes a first electrode, where the first electrode includes magnesium metal having a first surface, and a first coating in physical contact with the first surface and covering substantially all of the first surface, where the first coating has a first thickness, and the first coating is configured to transport a plurality of magnesium ions through the first thickness, such that a first portion of the plurality of magnesium ions are reversibly depositable as elemental magnesium onto the first surface.
1. A device comprising:
a first electrode comprising:
magnesium metal comprising a surface;
a current collector in physical contact with the magnesium metal; and
a coating, wherein:
the magnesium metal is positioned between the current collector and the coating,
the coating comprises a polymer and a magnesium-ion salt,
the coating is in physical contact with the surface and covers substantially all of the surface, and
the coating is configured such that a first portion of a plurality of magnesium ions may be reversibly transported through the coating and reversibly deposited as elemental magnesium onto the surface.
2. The device of claim 1 , wherein the magnesium metal is in the form of a particle, a film, a foil, a pellet, a cylinder, or a sphere.
3. The device of claim 1 , wherein the polymer comprises a polyacrylonitrile (PAN), a cyclized polyacrylonitrile (cPAN), a polyimide, a polyamide, a polystyrene, a polyethylene, a polyether, a polypyrrole, a polythiophene, a polyaniline, a polyacetylene, a polyparaphenylene, a polyethylene oxide, a polyethylene glycol, or a mixture thereof.
4. The device of claim 3 , wherein the polymer is cPAN.
5. The device of claim 1 , wherein the magnesium-ion salt comprises MgClO 4 , Mg(PF 6 ) 2 , Mg(CF 3 SO 3 ) 2 , MgCO 3 , Mg(BF4) 2 , Mg(NO 3 ) 2 , magnesium(II) bis(trifluoromethane sulfonyl) imide (Mg(TFSI) 2 ), or a mixture thereof.
6. The device of claim 1 , wherein the coating has a thickness between about 1 nm and about 500 nm.
7. The device of claim 1 , further comprising an electrolyte, wherein the electrolyte is in physical contact with the coating.
8. The device of claim 7 , wherein the electrolyte comprises a nitrile, a carbonate, or a mixture thereof.
9. The device of claim 8 , wherein the electrolyte comprises acetonitrile, propylene carbonate, or a mixture thereof.
10. The device of claim 7 , wherein the electrolyte further comprises a magnesium-ion salt.
11. The device of claim 10 , wherein the magnesium-ion salt of the electrolyte comprises MgClO 4 , Mg(PF 6 ) 2 , Mg(CF 3 SO 3 ) 2 , MgCO 3 , Mg(BF4) 2 , Mg(NO 3 ) 2 , magnesium(II) bis(trifluoromethane sulfonyl) imide (Mg(TFSI) 2 ), or a mixture thereof.
12. The device of claim 7 , further comprising:
a second electrode comprising V 2 O 5 , wherein:
a second portion of the plurality of magnesium ions are reversibly intercalated in the V 2 O 5 , and
the second electrode is in physical contact with the electrolyte.
13. The device of claim 1 , wherein the first portion is between about 80% and about 100% of the plurality of magnesium ions.
14. An electrode comprising:
magnesium metal comprising a surface;
a current collector in physical contact with the magnesium metal; and
a coating, wherein:
the magnesium metal is positioned between the current collector and the coating,
the coating comprises a polymer and a magnesium-ion salt,
the coating is in physical contact with the surface and covers substantially all of the surface, and
the coating is configured such that a plurality of magnesium ions may be reversibly transported through the coating and reversibly deposited as elemental magnesium onto the surface.
15. A method for charging and discharging a battery, the method comprising:
in a first electrode comprising a magnesium metal, reversibly converting a portion of the magnesium metal to a first plurality of Mg 2+ ions;
reversibly transferring a portion of the first plurality of Mg 2+ ions through a first coating comprising a polymer and a magnesium-ion salt where the first coating substantially covers the magnesium metal;
transferring the portion of the first plurality of Mg 2+ ions through an electrolyte in physical contact with the first coating;
transferring the portion of the first plurality of Mg 2+ ions through a second coating substantially covering a second electrode; and
intercalating the portion of the first plurality of Mg 2+ ions into the second electrode, wherein:
the second coating is in physical contact with the electrolyte,
the magnesium metal is in physical contact with a current collector, and
the magnesium metal is positioned between the current collector and the coating.
16. The method of claim 15 , further comprising:
deintercalating a second plurality of Mg 2+ ions from the second electrode;
transferring the second plurality of Mg 2+ ions through the second coating;
transferring the second plurality of Mg 2+ ions through the electrolyte;
reversibly transferring second plurality of Mg 2+ ions through the first coating;
reversibly converting the second plurality of Mg 2+ ions to elemental magnesium on the magnesium metal of the first electrode.