Electroplating lithiated transition metal oxides using low purity starting precursors
A method for electroplating (or electrodeposition) a lithiated transition metal oxide composition using low purity starting precursors. The method includes electrodepositing the electrochemically active material onto an electrode in an electrodeposition bath containing a non-aqueous electrolyte. The lithiated metal oxide can be used for various applications such as electrochemical energy storage devices including high power and high-energy lithium-ion batteries.
1. A method of forming a lithiated transition metal oxide onto the surface of a working electrode comprising the steps of:
(a) immersing a working electrode into a non-aqueous electrolyte comprising a lithium source and a transition metal source, wherein said lithium and transition metal sources have a purity ranging from about 50% to about 95% by weight;
(b) electrodepositing a lithiated transition metal oxide onto a surface of the working electrode from the electrolyte at a temperature in excess of the melting temperature of the non-aqueous electrolyte;
(c) removing the working electrode from the bath and;
(d) rinsing the electrodeposited lithiated transition metal oxide.
2. The method of claim 1 wherein the low purity lithium and transition metal sources have a purity ranging from about 50% to about 85% by weight.
3. The method of claim 1 wherein the low purity lithium source is selected from the group consisting of LiOH, Li 2 CO 3 LiF, LiCI, LiBr, LiI, LiNO 3 , LiNO 2 , Li 2 SO 4 , and combinations thereof.
4. The method of claim 1 wherein the low purity transition metal source is selected from the group consisting of MnCl 2 , MnSO 4 , Mn 2 O 3 , MnO 2 , Mn 3 O 4 , Mn(NO 3 ) 2 , CoO, Co 2 O 3 , Co 3 O 4 , CoOH 2 , CoCl 2 , CoSO 4 , Co(NO 3 ) 2 and combinations thereof.
5. The method of claim 1 wherein the non-aqueous electrolyte comprises an inorganic molten salt.
6. The method of claim 5 wherein at least 50% of the ions comprised by the inorganic molten salt electrolyte are inorganic ions.
7. The method of claim 5 wherein the inorganic molten salt electrolyte comprises a hydroxide salt, a halide salt, a sulfate salt, a nitrate salt, a nitrite salt, and combinations thereof.
8. The method of claim 7 wherein the inorganic molten salt electrolyte comprises a hydroxide salt selected from the group consisting of Li 2 SO 4 , LiOH, KOH, NaOH, RbOH, and CsOH, a halide salt selected from the group consisting of LiCI, LiF, KF, KCl, NaCl, NaF, LiBr, NaBr, KBr, LiI, NaI, KI, a nitrate salt selected from the group consisting of LiNO 3 , NaNO 3 , and KNO 3 , a nitrite salt selected from the group consisting of LiNO 2 , NaNO 2 , KNO 2 , a Li 2 SO 4 sulfate salt, and combinations thereof.
9. The method of claim 8 wherein the inorganic molten salt electrolyte comprises a hydroxide salt selected from the group consisting of LiOH, KOH, NaOH, and combinations thereof.
10. The method of claim 8 wherein the inorganic molten salt electrolyte comprises a Li 2 SO 4 sulfate salt.
11. The method of claim 1 wherein the working electrode comprises an electrically conductive material selected from the group consisting of metals, metal alloys, metallic ceramics, electrically conductive carbon, electrically conductive polymers, and electrically conductive composite materials.
12. The method of claim 11 wherein the working electrode is a planar foil with thickness ranging from 1 μm to 100 mm.
13. The method of claim 11 wherein the working electrode is a porous foam with porosity ranging from 1% to 99% porosity.
14. The method of claim 11 wherein the working electrode is a metal or metal alloy selected from the group consisting of aluminum, copper, chromium, cobalt, manganese, nickel, silver, gold, tin, platinum, palladium, zinc, tungsten, tantalum, rhodium, molybdenum, titanium, iron, zirconium, vanadium, and hafnium, and the alloys thereof.
15. The method of claim 1 wherein the source of the transition metal in the plating bath comprises an oxide, halide or sulfate of at least one transition metal.
16. The method of claim 1 wherein the transition metal source is selected from the group consisting of cobalt, manganese, nickel, copper, iron, chromium, vanadium, titanium, molybdenum, tungsten, and combinations thereof.
17. The method of claim 1 wherein the lithiated transition metal oxide is electrodeposited onto the surface(s) of a three-dimensional working electrode having an open pore porous structure.
18. The method of claim 1 wherein the lithiated transition metal oxide is conformally coated onto the working electrode.
19. The method of claim 1 wherein the thickness of the electrodeposited lithiated transition metal oxide ranges from about 10 nm to about 500 μm.
20. The method of claim 1 wherein the electrodeposited lithiated transition metal oxide is lithium cobalt oxide characterized by an XRD spectrum containing a doublet peak at approximately between 63 and 70 2⊖ degrees.