Lithium metal dispersion in secondary battery anodes
View Patent ↗The present invention is a secondary battery having a high specific capacity and good cycleability, and that can be used safely. The secondary battery is manufactured to include an anode formed from a host material capable of absorbing and desorbing lithium in an electrochemical system such as a carbonaceous material, and lithium metal dispersed in the host material. The anodes of the invention are combined with a cathode including an active material, a separator that a separates the cathode and the anode, and an electrolyte in communication with the cathode and the anode. The present invention also includes a method of preparing an anode and a method of operating a secondary battery including the anode of the invention.
1. An electrochemical cell, comprising:
(A) a cathode comprising an active material capable of being electrochemically lithiated, wherein the cathode does not comprise electrochemically removable lithium prior to the initial charge;
(B) an anode separated from said cathode by a separating material, wherein the anode comprises a host material capable of absorbing and desorbing lithium in an electrochemical system and finely divided lithium metal powder dispersed within said host material, wherein the amount of lithium dispersed in the anode is no more than the maximum amount sufficient to intercalate in, alloy with and/or be absorbed by the host material after activation; and
(C) an electrolyte in electrochemical communication with the cathode and the anode.
2. The electrochemical cell of claim 1 , wherein the anode further comprises a binder polymer selected from the group consisting of polyvinylidene fluoride, ethylene propylene diene terpolymer, ethylene acrylic acid, ethylene vinyl acetate, and styrene-butadiene rubber.
3. The electrochemical cell of claim 1 , wherein said host material comprises at least one material selected from the group consisting of carbonaceous materials, silicon, tin, tin oxides, composite tin alloys, transition metal oxides, lithium metal nitrides, graphite, carbon black, and lithium metal oxides.
4. The electrochemical cell of claim 1 , wherein the finely divided lithium metal powder has a mean particle size of less than about 20 microns.
5. The electrochemical cell of claim 1 , wherein the finely divided lithium metal powder comprises a stabilized low pyrophorosity powder.
6. The electrochemical cell of claim 1 , wherein the finely divided lithium metal powder has a mean particle size of less than about 10 microns.
7. The electrochemical cell of claim 1 , wherein the finely divided lithium metal powder comprises a pyrophoric powder.
8. A battery, comprising:
at least one electrochemical cell, wherein the at least one electrochemical cell comprises
(A) a cathode comprising an active material capable of being electrochemically lithiated, wherein the cathode does not comprise electrochemically removable lithium prior to the initial charge;
(B) an anode separated from the cathode by a separating material, wherein the anode comprises a host material capable of absorbing and desorbing lithium in an electrochemical system and finely divided lithium metal powder dispersed with the host material, wherein the amount of lithium dispersed in the anode is no more than the maximum amount sufficient to intercalate in, alloy with and/or be absorbed by the host material after activation; and
(C) an electrolyte in electrochemical communication with the cathode and the anode.
9. The battery of claim 8 , wherein the battery comprises at least two electrochemical cells combined in series.
10. The battery of claim 8 , wherein the anode further comprises a binder polymer selected from the group consisting of polyvinylidene fluoride, ethylene propylene diene terpolymer, ethylene acrylic acid, ethylene vinyl acetate, and styrene-butadiene rubber.
11. The battery of claim 8 , wherein the finely divided lithium metal powder has a mean particle size of less than about 20 microns.
12. The battery of claim 8 , wherein the finely divided lithium metal powder has a mean particle size of less than about 10 microns.
13. The battery of claim 8 , wherein the finely divided lithium metal powder comprises a pyrophoric powder.
14. The battery of claim 8 , wherein the finely divided lithium metal powder comprises a stabilized low pyrophorosity powder.