Electrodes including novel binders and methods of making and using the same
Provided are electrode compositions for lithium-ion electrochemical cells that include novel binders. The novel binders include lithium polysalts of carboxylic and sulfonic acids, lithium salts of copolymers of acids, lithium polysulfonate fluoropolymers, a cured phenolic resin, cured glucose, and combinations thereof.
1. An electrode composition for a negative electrode comprising:
a powdered material capable of undergoing lithiation and delithiation, wherein the powdered material is selected from tin, a tin alloy, silicon, a silicon alloy, and a combination thereof; and
a nonelastic binder comprising a lithium polyacrylate,
wherein the lithium polyacrylate is derived from homopolymers or copolymers of acrylic or methacrylic acid.
2. An electrode composition for a negative electrode of claim 1
wherein more than 100% to about 107% of the acrylic or methacrylic acid groups have been neutralized.
3. The electrode composition according to claim 2 , wherein the powdered material further comprises a material selected from silver, bismuth, carbon, lead, antimony, germanium, zinc, gold, platinum, palladium, arsenic, aluminum, gallium, indium, thallium, molybdenum, niobium, tungsten, tantalum, vanadium, chromium, zirconium, yttrium, a lanthanide, an actinide, and combinations thereof.
4. An electrode composition for a negative electrode comprising
a powdered material capable of undergoing lithiation and delithiation, wherein the powdered material is selected from tin, a tin alloy, silicon, a silicon alloy, and a combination thereof; and
a binder selected from a lithium polystyrenesulfonate, a lithium polysulfonate fluoropolymer, a lithium salt of a copolymer that includes maleic acid or a sulfonic acid, a cured phenolic resin, cured glucose, and combinations thereof.
5. The composition according to claim 4 wherein the lithium polysulfonate is selected from a polystyrenesulfonate and a polysulfonate fluoropolymer.
6. The composition according to claim 5 wherein the lithium polysulfonate fluoropolymer is derived from a polysulfonic acid fluoropolymer that comprises a substantially fluorinated backbone and pendant groups, wherein the pendent groups comprise:
HO 3 S—(CFR f ) a (CFR f ) b —Z 1 —(CFR f ) c (CFR f ) d —Z 2 —
wherein each of a, b, c, and d independently range from 0-3, c+d≧1, Z 1 and Z 2 =O or a single bond, and each R f is independently either F or a substantially fluorinated, branched or unbranched fluoroalkyl, fluoroalkoxyl, or fluoroether group that contains 1 to 15 carbon atoms and 0 to 4 oxygen atoms in the fluoroalkyl, fluoroalkoxyl, or fluoroether chain.
7. The composition according to claim 4 wherein the binder is selected from a poly(ethylene-alt-maleic acid) Li salt, poly(acrylic acid-co-maleic acid) Li salt, poly(methyl vinyl ether-alt-maleic acid) Li salt.
8. The composition according to claim 4 , wherein the powdered material further comprises a material selected from silver, tin, bismuth, carbon, lead, antimony, germanium, zinc, gold, platinum, palladium, arsenic, aluminum, gallium, indium, thallium, molybdenum, niobium, tungsten, tantalum, iron, copper, titanium, vanadium, chromium, nickel, cobalt, zirconium, yttrium, a lanthanide, an actinide, and combinations thereof.
9. The composition according to claim 1 or 4 , wherein the powdered material comprises from about 65 to about 85 mole % silicon, from about 5 to about 12 mole % iron, from about 5 to about 12 mole % titanium, and from about 5 to about 12 mole % carbon.
10. An electrochemical cell comprising:
at least one electrode that comprises a composition according to claim 1 .
11. A battery pack comprising at least one cell according to claim 10 .
12. A method of making a negative electrode comprising:
providing a current collector;
providing a powdered material capable of undergoing lithiation and delithiation, wherein the powdered material is selected from tin; a tin alloy; silicon; silicon alloy; and a combination thereof; and
applying to the current collector a coating that comprises the powdered material and a nonelastic binder comprising a lithium polyacrylate,
wherein the lithium polyacrylate is derived from homopolymers or copolymers of acrylic or methacrylic acid, and
wherein more than 100% to about 107% of the acrylic or methacrylic acid groups have been neutralized.
13. The method according to claim 12 wherein applying to the current collector a coating further comprises:
mixing the powdered material with a solution of the binder to form a dispersion;
milling the dispersion to form a coatable mixture;
coating the mixture onto the current collector; and
drying the coated current collector.