Process to produce cathode materials for rechargeable Li batteries
This invention provides a method for the production of high capacity cathode materials for use in rechargeable lithium batteries. Traditional methods for producing lithium mixed metal oxide cathode materials typically generate large amounts of effluent which effluent must be treated prior to discharge. The present process uses mixed metals as raw materials in a wet chemical reaction in order to make high-quality precursors which can be used to prepare high-quality cathode materials after lithiation. As a key feature, in the precursor preparation process, the bulk of the aqueous solution used for the wet chemical reaction is recycled back to the reactor, so that the total process has little or no effluent generated during production of the cathode precursor material.
1 . A method of producing an isolated cathode active material precursor, comprising:
providing an aqueous solution with a pH of greater than 7;
adding a first metal to the aqueous solution to form a reaction solution;
selecting the first metal from at least one element of nickel, manganese, cobalt, aluminum, and magnesium;
forming a product solution by adding an oxidant and a second metal to the reaction solution, wherein the forming of the product solution further comprises forming a cathode active material precursor comprising the first metal and the second metal;
selecting the second metal from at least two elements of nickel, manganese, cobalt, aluminum, magnesium, zirconium, yttrium, titanium, vanadium, molybdenum and combinations thereof, wherein the selecting of the second metal comprises selecting the first metal other than the selecting of the second metal; and
isolating the cathode active material precursor from at least a portion of the product solution and thereby forming a filtrate solution and an isolated cathode active material precursor.
2 . The method of claim 1 , wherein the forming of the product solution by adding the first metal to the aqueous solution further comprises adding a mixed metal hydroxide to the aqueous solution.
3 . The method of claim 1 , wherein the providing the aqueous solution further comprises providing the aqueous solution having the pH of about 7.5 to about 13.
4 . The method of claim 1 , wherein the aqueous solution further comprises an acid selected from the group consisting of sulfuric acid, nitric acid, acetic acid or combinations thereof.
5 . The method of claim 1 , wherein the aqueous solution further comprises an alkaline material selected from lithium hydroxide, lithium oxide, sodium hydroxide, sodium oxide, potassium hydroxide, potassium oxide, and ammonia.
6 . The method of claim 1 , wherein the aqueous solution further comprises a conductive salt.
7 . The method of claim 6 , wherein the conductive salt is selected from the group consisting of a sulfate salt, an acetate salt, a nitrate salt, a chloric salt and combinations thereof.
8 . The method of claim 6 , wherein the conductive salt comprises a cation selected from the group consisting of sodium, lithium, potassium, ammonium and combinations thereof.
9 . The method of claim 1 , wherein the aqueous solution further comprises an additional anion.
10 . The method of claim 9 , wherein the additional anion is selected from the group consisting of borate, bromide, iodide, chloride, sulphate, formate, acetate and combinations thereof.
11 . The method of claim 1 , wherein the aqueous solution comprises a cation.
12 . The method of claim 11 , wherein the cation is selected from the group consisting of sodium, potassium, lithium and combinations thereof.
13 . The method of claim 1 , wherein the aqueous solution further comprises a complexing agent.
14 . The method of claim 13 , wherein the complexing agent comprises ammonia and ammonium.
15 . The method of claim 1 , wherein adding the oxidant and the second metal to the reaction solution to form the product solution further comprises adding cathode active material precursor particles to the reaction solution.
16 . The method of claim 1 , further comprising combining the filtrate solution with the product solution to form additional cathode active material precursor.
17 . The method of claim 1 , further comprising selecting the oxidant from oxygen, nitric acid and combinations thereof.
18 . The method of claim 1 , further comprising isolating unreacted metals comprising the first and second metals from the filtrate solution, and treating the unreacted metals with an acid to form additional cathode active material precursor.
19 . The method of claim 18 , further comprising selecting the acid from nitric acid, ammonia, ammonium and combinations thereof.
20 . The method of claim 18 , further comprising additionally treating the unreacted metals and selecting the additional treatment from milling, washing, and combinations thereof.
21 . A method of forming a cathode active material, comprising:
providing an aqueous solution with a pH of greater than 7;
adding a first metal to the aqueous solution to form a reaction solution;
selecting the first metal from at least one element of nickel, manganese, cobalt, aluminum and magnesium;
forming a product solution by adding an oxidant and a second metal to the reaction solution, wherein the forming of the product solution further comprises forming a cathode active material precursor comprising the first metal and the second metal;
selecting the second metal from at least two elements of nickel, manganese, cobalt, aluminum, magnesium, zirconium, yttrium, titanium, vanadium, molybdenum and combinations thereof, wherein the selecting of the second metal comprises selecting the first metal other than the selecting of the second metal;
isolating the cathode active material precursor from at least a portion of the product solution and thereby forming a filtrate solution and an isolated cathode active material precursor;
forming a final mixture comprising the isolated cathode active material precursor and a lithium containing compound; and
calcinating the final mixture thereby forming a calcinated final mixture comprising a cathode active material.
22 . The method of claim 21 , wherein the final mixture further comprises a dopant.
23 . The method of claim 21 , wherein the lithium containing compound comprises lithium hydroxide, lithium carbonate, or combinations thereof.
24 . The method of claim 21 , wherein the calcination is performed at a temperature of about 600° C. to about 1100° C.
25 . A method of forming an energy storage device, comprising:
providing an aqueous solution with a pH of greater than 7;
adding a first metal to the aqueous solution to form a reaction solution;
selecting the first metal from at least one element of nickel, manganese, cobalt, aluminum and magnesium;
forming a product solution by adding an oxidant and a second metal to the reaction solution, wherein the forming of the product solution further comprises forming a cathode active material precursor comprising the first metal and the second metal;
selecting the second metal from at least two elements of nickel, manganese, cobalt, aluminum, magnesium, zirconium, yttrium, titanium, vanadium, molybdenum and combinations thereof, wherein the selecting of the second metal comprises selecting the first metal other than the selecting of the second metal;
isolating the cathode active material precursor from at least a portion of the product solution and thereby forming a filtrate solution and an isolated cathode active material precursor;
forming a final mixture comprising the isolated cathode active material precursor and a lithium containing compound;
calcinating the final mixture thereby forming a calcinated final mixture comprising a cathode active material;
forming a cathode, wherein cathode formation comprises depositing the cathode active material on a current collector; and
inserting the cathode, an anode and a separator within a housing, wherein the separator is positioned between the anode and the cathode.