ELECTRODE MATERIALS AND PROCESSES FOR THEIR PREPARATION
Here is described an electrode material comprising an electrochemically active metallic film and an organic compound, e.g. an indigoid compound (indigo blue or a derivative or precursor thereof). Processes for the preparation of the electrode material and electrodes containing the material, as well as to the electrochemical cells and their use are also contemplated.
1 . An electrode material comprising a film of a metallic material as electrochemically active material, and a compound of Formula I:
wherein,
R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , and R 8 are each independently selected from a hydrogen atom, a group selected from halogen, optionally halogenated alkyl, cycloalkyl, or aryl, CN, —NO 2 , —SO 2 OM 2 , —OP(O)(OM 2 ) 2 , —P(O)(OM 2 ) 2 , or —C(O)OM 2 , wherein M 2 is a cation of an alkali or alkaline earth metal, or a —OC(O)alkyl, —SO 2 NH 2 , —SO 2 NHalkyl, or —SO 2 N(alkyl) 2 group;
X 1 is NH; and
i. a, c and e are single bonds, b and d are double bonds, X 2 is O, and M 1 is H or a cation of an alkali or alkaline earth metal ion forming a salt with X 2 wherein the ratio of cation to the rest of the compound of Formula I provides electroneutrality; or
ii. a, c and e are double bonds, b and d are single bonds, X 2 is O or NOH (oxime), and M 1 is absent;
or a geometric isomer of a compound of Formula I;
or a carbohydrate complex or conjugate thereof; and
wherein the metallic material is selected from an alkali or alkaline earth metal, and alloys thereof where the alkali or alkaline earth metal is the major component.
2 . The electrode material of claim 1 , wherein R 2 and R 6 are the same and selected from halogen, optionally halogenated alkyl, —CN, and —SO 2 OM 2 , and/or R 3 and R 7 are the same and selected from halogen, optionally halogenated alkyl, —CN, and —SO 2 OM 2 .
3 . The electrode material of claim 2 , wherein R 2 and R 6 R 7 are the same and selected from F and —CN, and/or R 3 and R 7 are the same and selected from F and —CN.
4 . The electrode material of claim 1 , wherein each of R 1 to R 8 are each a hydrogen atom.
5 . The electrode material of claim 1 , wherein a, c and e are single bonds, b and d are double bonds, X 2 is O, and M 1 is H or a cation of an alkali or alkaline earth metal ion forming a salt with X 2 .
6 . The electrode material of claim 5 , wherein M 1 is a cation of the same metal as the metal of the film of metallic material.
7 . The electrode material of claim 1 , wherein a, c and e are double bonds, b and d are single bonds, X 2 is O, and M 1 is absent.
8 . The electrode material of claim 1 , wherein the compound is selected from:
9 . The electrode material of claim 1 , wherein the compound is selected from indigo blue, indigo carmine, and leuco-indigo or a M 1 salt thereof.
10 . The electrode material of claim 1 , wherein the compound is indigo blue, leuco-indigo or a M 1 salt thereof, or a combination thereof.
11 . The electrode material of claim 1 , wherein the metallic film is a film of an alkali or alkaline earth metal.
12 . The electrode material of claim 1 , wherein the metallic film is a film of lithium alloy, sodium alloy, or magnesium alloy.
13 . The electrode material of claim 1 , wherein the metallic film is a film of lithium or a lithium alloy.
14 . The electrode material of claim 12 , wherein the lithium alloy comprises at least 75% of lithium by weight.
15 . The electrode material of claim 1 , wherein the metallic film has a thickness between about 5 μm and about 200 μm.
16 . The electrode material of claim 1 , wherein said compound is at a concentration of about 2 wt % or less.
17 . An electrode comprising an electrode material as defined in claim 1 , on a current collector, preferably being a nickel or copper film.
18 . An electrochemical cell comprising an electrode containing an electrode material as defined in claim 1 , an electrolyte and a counter-electrode.
19 . An electrochemical cell comprising an electrode as defined in claim 17 , an electrolyte and a counter-electrode.
20 . A battery comprising at least one electrochemical cell as defined in claim 18 , preferably a lithium battery or a lithium-ion battery.