High capacity alkaline cells
The present invention relates to a high capacity electrochemical cell including a cathode that can contain an oxide of copper as an active material, an anode, an electrolyte, and a separator disposed between the anode and the cathode. The oxide can have surface area greater than 0.5 m 2 /g, and the cathode can include an additive that increases the discharge voltage of the cell. In some cases the additive has a lower voltage than the oxide alone. The additive can have a surface area within the range defined by a lower limit of 0.5 m 2 /g and an upper limit of 100 m 2 /g. The anode can include a quantity of mercury below 0.025%.
1 . An electrochemical cell comprising:
an anode;
a cathode containing an oxide of copper, the oxide of copper having a surface area greater than 0.5 m 2 /g; and
a separator disposed between the anode and the cathode.
2 . The electrochemical cell as recited in claim 1 , wherein the oxide of copper is included in particle form.
3 . The electrochemical cell as recited in claim 1 , wherein the anode includes zinc having a particle size distribution within a window of 200 microns.
4 . The electrochemical cell as recited in claim 3 , wherein the particle size distribution is substantially between 100 and 250 microns.
5 . The electrochemical cell as recited in claim 4 , wherein the particle size distribution is substantially centered around 100 microns.
6 . The electrochemical cell as recited in claim 3 , wherein the particle size distribution is substantially centered around 175 microns.
7 . The electrochemical cell as recited in claim 3 , wherein the particle size distribution is substantially centered around 250 microns.
8 . The electrochemical cell as recited in claim 3 , wherein the particle size distribution is substantially centered around 300 microns.
9 . The electrochemical cell as recited in claim 1 , wherein the cathode further comprises a metal oxide additive.
10 . The electrochemical cell as recited in claim 9 , wherein the additive further comprises an electrode material, the electrode material providing a higher operating voltage vs. zinc in an initial portion of discharge compared to the oxide of copper.
11 . The electrochemical cell as recited in claim 10 , wherein the additive is selected from the group consisting of EMD, CMD, NiO, NiOOH, Cu(OH) 2 , Cobalt Oxide, PbO 2 , AgO, Ag 2 O, Cu 2 Mn 2 O 4 , and Cu 2 Ag 2 O 4 , Cu 2 Ag 2 O 3 , CuAgS, and CuAg 3 S.
12 . The electrochemical cell as recited in claim 1 , wherein the cathode further comprises a copper based mixed oxide material identified generally by M x Cu y O z , wherein:
M is a soluble element capable of producing mixed oxide compounds or complexes;
1≦x≦5;
1≦y≦5; and
1≦z≦20.
13 . The electrochemical cell as recited in claim 12 , wherein M is selected from the group consisting of Mn, Ni, Co, Fe, Sn, V, Mo, Pb, and Ag.
14 . The electrochemical cell as recited in claim 12 , wherein the copper based mixed oxide material is further identified by AM x Cu y O z , wherein A is a metal.
15 . The electrochemical cell as recited in claim 1 , wherein the cathode further comprises an additive that, when used alone, has a lower discharge voltage than the oxide, wherein the combined oxide and additive produce a higher discharge voltage than either the oxide or the additive alone.
16 . The electrochemical cell as recited in claim 15 , wherein the additive is selected from the group consisting of elemental sulfur, selenium, tellurium, and compounds thereof.
17 . The electrochemical cell as recited in claim 16 , wherein the additive comprises a sulfide of copper.
18 . The electrochemical cell as recited in claim 17 , wherein the additive comprises CuS.
19 . The electrochemical cell as recited in claim 18 , wherein the cathode further comprises a molar ratio of CuO/CuS substantially between 0.5:1 and 1.5:1.
20 . The electrochemical cell as recited in claim 19 , wherein the molar ratio is substantially 1:1.
21 . The electrochemical cell as recited in claim 1 , wherein the oxide has a surface area within the range defined by a lower limit of 0.5 m 2 /g and an upper limit of 100 m 2 /g.
22 . The electrochemical cell as recited in claim 1 , wherein the oxide has a surface area within the range defined by a lower limit of 5 m 2 /g and an upper limit of 30 m 2 /g.
23 . The electrochemical cell as recited in claim 21 , wherein the surface area is substantially 60 m 2 /g.
24 . The electrochemical cell as recited in claim 21 , wherein the oxide has a particle size within the range defined by a lower limit of 0.1 micron and an upper limit of 150 microns.
25 . The electrochemical cell as recited in claim 24 , wherein the range is further defined by a lower limit of 1 micron.
26 . The electrochemical cell as recited in claim 24 , wherein the range is further defined by an upper limit of 50 microns.
27 . An electrochemical cell comprising:
an anode;
a cathode containing an oxide of copper, the oxide having a surface area >0.5 m 2 /g and an additive to the oxide that has a lower discharge voltage than the oxide, wherein the combined oxide and additive produce a higher discharge voltage than either the oxide or the additive alone; and
a separator disposed between the anode and cathode.
28 . The electrochemical cell as recited in claim 27 , wherein the oxide comprises copper oxide.
29 . The electrochemical cell as recited in claim 28 , wherein the additive comprises a sulfide of copper.
30 . The electrochemical as recited in claim 29 , wherein the sulfide comprises CuS.
31 . The electrochemical cell as recited in claim 30 , wherein the cathode further comprises a molar ratio of CuO/CuS substantially between 0.5:1 and 1.5:1.
32 . The electrochemical cell as recited in claim 31 , wherein the cathode further comprises a molar ratio of CuO/CuS substantially between 0.8:1 and 1.2:1.
33 . The electrochemical cell as recited in claim 31 , wherein the molar ratio is substantially 1:1.
34 . The electrochemical cell as recited in claim 27 , wherein the separator (i) comprises a polymer and (ii) is configured to effectively limit the migration of anode-fouling soluble species from the cathode to the anode.
35 . The electrochemical cell as recited in claim 27 , wherein the separator further comprises a polymer film having opposing sides, the polymer film having the ability to effectively limit the migration of soluble copper species and soluble sulfur species from one side of the polymer film to the other side of the polymer film.
36 . The electrochemical cell as recited in claim 27 , wherein the separator (i) further comprises a polyvinyl alcohol film and (ii) is configured to effectively limit anode-fouling soluble species from migrating to the anode.
37 . The electrochemical cell as recited in claim 36 , wherein substantially all fluid communication between the anode and the cathode is through the separator, and wherein the separator effectively limits the migration of soluble copper species and soluble sulfur species through the separator from the cathode to the anode.
38 . The electrochemical cell as recited in claim 27 , further comprising an alkaline aqueous bulk electrolyte in fluid communication with the anode and the cathode, substantially all of the fluid communication being through the separator, the separator being adapted to effectively limit migration of at least one anode-fouling soluble species through the separator from the cathode to the anode.
39 . The electrochemical cell as recited in claim 27 , wherein the additive is selected from the group consisting of elemental sulfur, selenium, tellurium, and compounds thereof.
40 . An electrochemical cell comprising:
an anode;
a cathode containing an oxide of copper and an additive to the oxide, the additive having a surface area within the range defined by a lower limit of 0.5 m 2 /g and an upper limit of 100 m 2 /g, wherein the additive has a lower discharge voltage than the oxide, wherein the combined oxide and additive have a higher discharge voltage than either the oxide or the additive alone; and
a separator disposed between the anode and cathode.
41 . The electrochemical cell as recited in claim 40 , wherein the additive comprises a sulfide of copper.
42 . The electrochemical cell as recited in claim 41 , wherein the additive comprises CuS.
43 . The electrochemical cell as recited in claim 42 , wherein the cathode further comprises a molar ratio of CuO/CuS substantially between 0.5:1 and 1.5:1.
44 . The electrochemical cell as recited in claim 43 , wherein the cathode further comprises a molar ratio of CuO/CuS substantially between 0.8:1 and 1.2:1.
45 . The electrochemical cell as recited in claim 44 , wherein the molar ratio is substantially 1:1.
46 . The electrochemical cell as recited in claim 40 , wherein the separator (i) comprises a polymer and (ii) is configured to effectively limit the migration of anode-fouling soluble species from the cathode to the anode.
47 . The electrochemical cell as recited in claim 40 , wherein the separator further comprises a polymer film having opposing sides, the polymer film having the ability to effectively limit the migration of soluble copper species, soluble silver species, and soluble sulfur species from one side of the polymer film to the other side of the polymer film.
48 . The electrochemical cell as recited in claim 40 , wherein the separator (i) further comprises a polyvinyl alcohol film and (ii) is configured to effectively limit soluble copper species, soluble silver species, and soluble sulfur species from migrating to the anode.
49 . The electrochemical cell as recited in claim 40 , wherein substantially all fluid communication between the anode and the cathode is through the separator, the separator being adapted to effectively limit the migration of at least one anode-fouling soluble species through the separator from the cathode to the anode.
50 . The electrochemical cell as recited in claim 40 , wherein the separator further comprises a polymer film having opposing sides, the polymer film having the ability to effectively limit the migration of soluble copper species, soluble silver species, and soluble sulfur species from one side of the polymer film to the other side of the polymer film.
51 . An electrochemical cell comprising:
an anode;
a cathode including a component that generates an anode-fouling sulfur species;
a separator disposed between the anode and the cathode;
an electrolyte; and
an additive that interacts with at least a portion of the sulfur species to reduce anode-fouling by the species.
52 . The electrochemical cell as recited in claim 5 1 , wherein the interaction reduces the solubility of the sulfur species.
53 . The electrochemical cell as recited in claim 52 , wherein the sulfur species has a reduced ability to migrate to the anode when combined with the additive.
54 . The electrochemical cell as recited in claim 51 , wherein the additive binds to the sulfur species to reduce migration to the anode.
55 . The electrochemical cell as recited in claim 54 , wherein the bound product is larger in size than the anode-fouling soluble species.
56 . The electrochemical cell as recited in claim 51 , wherein the interaction between the additive at least a portion of the sulfur species is a reaction that produces a reaction product.
57 . The electrochemical cell as recited in claim 56 , wherein the reaction product has a solubility product of less than 2×10 −25 .
58 . The electrochemical cell as recited in claim 57 , wherein the solubility product of the reaction product is about 2×10 −25 .
59 . The electrochemical cell as recited in claim 5 1 , wherein the additive reduces migration of the sulfur species through the separator.
60 . The electrochemical cell as recited in claim 51 , wherein the additive mixes with the sulfur species to form a sulfide.
61 . The electrochemical cell as recited in claim 60 , wherein the sulfide is larger than the anode-fouling sulfur species.
62 . The electrochemical cell as recited in claim 5 1 , wherein the sulfur species is selected from the group consisting of a sulfide, sulfate, sulfite, and thiosulfate.
63 . The electrochemical cell as recited in claim 51 , wherein the additive is selected from the group consisting of bismuth oxide, bismuth hydroxide, and zinc oxide.
64 . The electrochemical cell as recited in claim 51 , further comprising an alkaline aqueous bulk electrolyte having a pH value, wherein the separator includes a polymeric material and an alkaline aqueous electrolyte being retained in the separator, the retained electrolyte having a pH value lower than that of the bulk electrolyte.
65 . The electrochemical cell as recited in claim 51 , wherein the separator (i) comprises a polymer and (ii) is configured to effectively limit the migration of anode-fouling species from the cathode to the anode.
66 . The electrochemical cell as recited in claim 51 , wherein the separator further comprises a polymer film having opposing sides, the polymer film having the ability to effectively limit the migration of soluble copper species and soluble sulfur species from one side of the polymer film to the other side of the polymer film.
67 . The electrochemical cell as recited in claim 51 , wherein the separator (i) further comprises a polyvinyl alcohol film and (ii) is configured to effectively limit soluble copper species and soluble sulfur species from migrating to the anode.
68 . The electrochemical cell as recited in claim 51 , wherein substantially all fluid communication between the anode and the cathode is through the separator, the separator being adapted to effectively limit the migration of at least one anode-fouling soluble species through the separator from the cathode to the anode.
69 . An electrochemical cell comprising:
an anode;
a cathode containing an oxide of copper and an additive to the oxide, the cathode having a density between about 3.5 g/cc and 4.5 g/cc; and
a separator disposed between the anode and the cathode.
70 . The electrochemical cell as recited in claim 69 , wherein the oxide comprises CuO.
71 . The electrochemical cell as recited in claim 70 , wherein the additive comprises sulfide of copper.
72 . The electrochemical cell as recited in claim 71 , wherein the sulfide of copper comprises CuS.
73 . An electrochemical cell comprising:
an anode;
a cathode containing an oxide of copper;
a separator disposed between the anode and the cathode; and
an electrolyte facilitating ionic transport through the separator between the cathode and anode,
wherein the cell achieves an anode capacity/cell volume ratio>0.5 Ah/cc.
74 . The electrochemical cell as recited in claim 73 , wherein the anode capacity/cell volume ratio is between 0.55 and 0.9 Ah/cc.
75 . The electrochemical cell as recited in claim 73 , wherein the anode capacity/cell volume ratio is between 0.55 and 0.7 Ah/cc.
76 . An electrochemical cell comprising:
an anode including a quantity of mercury below 0.025%;
a cathode containing an oxide of copper; and
a separator disposed between the anode and the cathode.
77 . The electrochemical cell as recited in claim 76 , wherein the oxide comprises CuO.
78 . The electrochemical cell as recited in claim 76 , wherein the quantity of mercury is substantially zero.
79 . The electrochemical cell as recited in claim 76 , wherein the cathode further comprises an additive having a voltage greater than that of CuO.
80 . The electrochemical cell as recited in claim 76 , wherein the cathode further comprises an additive that, when used alone, has a lower discharge voltage than the oxide, wherein the combined oxide and additive produce a higher discharge voltage than either the oxide or the additive alone.
81 . The electrochemical cell as recited in claim 80 , wherein the additive is selected from the group consisting of elemental sulfur, selenium, tellurium, and compounds thereof.
82 . A method for selecting a combination of at least two materials to be included into a cathode of an electrochemical cell, the method comprising:
(A) identifying a cathode active material and an additive each having a respective open circuit voltage;
(B) determining an open circuit voltage for a combination of the cathode active material and the additive; and
(C) selecting the combination when the open circuit voltage of the combination is greater than the open circuit voltage of the cathode active material or the additive alone.
83 . The method as recited in claim 82 , wherein the cathode active material comprises an oxide of copper and the additive comprises a sulfide of copper.
84 . The method as recited in claim 83 , wherein the oxide of copper comprises CuO and the sulfide of copper comprises CuS.
85 . A method for selecting a combination of at least two materials to be included in a cathode of an electrochemical cell, the method comprising:
(A) identifying a cathode active material and an additive, each having a respective Gibbs' Free Energy of reduction reaction;
(B) determining the change in Gibbs' Free Energy for the reduction reaction of a combination of the cathode active material and the additive; and
(C) selecting the combination when the change in Gibbs' Free Energy of the reduction reaction of the combination is greater than the Gibbs' Free Energy change for the reduction reaction of the cathode active material or the additive alone.
86 . The method as recited in claim 85 , wherein the active cathode material comprises an oxide of copper and the additive comprises a sulfide of copper.
87 . The method as recited in claim 86 , wherein the oxide of copper comprises CuO and the sulfide of copper comprises CuS.
88 . The method as recited in claim 85 , wherein step (A) further comprises identifying copper oxide and copper sulfide.
89 . The method as recited in claim 85 , wherein the combination comprises CuO/CuS.