Anodes Comprising an Electrically Conductive Layer Between an Anode-Active Material and a Current Collector, and Electrochemical Devices Incorporating Such Anodes
A method of forming anodes for electrochemical devices by laminating a metal foil to a current collector and creating anode-active-material patches, composed of the metal foil, that are spaced from one another by inter-patch regions, wherein each inter-patch region provides a location for forming one or more electrical tabs of the finished anodes. The method can further include applying conductive-coating patches to the current collector prior to laminating the metal foil to the current collector, wherein each conductive-coating patch corresponds to one of the anode-active-material patches. In some embodiments, the conductive-coating patches can assist with forming the anode-active-material patches and/or can improve the cycling performance of an electrochemical device made using anodes made therewith. Anodes containing anode-active material and conductive coatings applied to current collectors are also disclosed.
1 . An anode for an electrochemical device, the anode comprising:
a current collector having a thickness and an active region, wherein the active region has first and second sides on opposite sides of the thickness;
a first anode-active metal layer secured to the current collector on the first side of the active region; and
a first electrically conductive layer between the current collector and the first anode-active metal layer, wherein the first electrically conductive layer secures the first anode-active metal layer to the current collector.
2 . The anode of claim 1 , wherein the first anode-active metal layer comprises a first metal foil and the first electrically conductive layer is provided to secure the first metal foil to the current collector.
3 . The anode of claim 1 , wherein the first electrically conductive layer comprises an electrically-conductive-carbon layer.
4 . The anode of claim 3 , wherein the electrically-conductive-carbon layer consists essentially of electrically-conductive-carbon particles and a binder.
5 . The anode of claim 4 , wherein the binder is selected from the group consisting of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, carboxymethyl cellulose, styrene-butadiene rubber, poly(acrylic acid), and any mixture thereof.
6 . The anode of claim 4 , wherein the electrically-conductive-carbon particles are present in an amount of about 50 wt. % to about 90 wt. % of the electrically-conductive-carbon layer.
7 . The anode of claim 3 , wherein the electrically-conductive-carbon layer has a thickness in a range of about 0.1 μm to about 5 μm.
8 . The anode of claim 3 , wherein the electrically-conductive-carbon layer has a thickness in a range of about 0.5 μm to about 2 μm.
9 . The anode of claim 3 , wherein the electrically-conductive-carbon layer has a thickness of about 1 μm.
10 . The anode of claim 3 , wherein the electrically-conductive-carbon layer is present in an areal loading of about 0.1 g/m 2 to about 2 g/m 2 .
11 . The anode of claim 1 , wherein the current collector comprises copper, and the first anode-active metal layer comprises lithium.
12 . The anode of claim 11 , wherein the current collector has a thickness in a range of about 4 μm to about 10 μm, and the first metal foil has a thickness in a range of about 15 μm to about 25 μm.
13 . The anode of claim 11 , wherein the first electrically-conductive layer consists essentially of electrically-conductive-carbon particles and a binder.
14 . The anode of claim 13 , wherein the electrically-conductive-carbon particles are present in an amount of about 50 wt. % to about 90 wt. % of the electrically-conductive-carbon layer.
15 . The anode of claim 11 , wherein the first electrically conductive layer has a thickness in a range of about 0.1 μm to about 5 μm.
16 . The anode of claim 11 , wherein the first electrically conductive layer has a thickness in a range of about 0.5 μm to about 2 μm.
17 . The anode of claim 11 , wherein the first electrically conductive layer has a thickness of about 1 μm.
18 . The anode of claim 11 , wherein the first electrically conductive layer is present in an areal loading of about 0.1 g/m 2 to about 2 g/m 2 .
19 . The anode of claim 1 , further comprising:
a second anode-active metal layer secured to the current collector on the second side of the active region; and
a second electrically conductive layer between the current collector and the second anode-active metal layer, wherein the second electrically conductive layer secures the second anode-active metal layer to the current collector.
20 . The anode of claim 19 , wherein the second anode-active metal layer comprises a second metal foil.
21 . The anode of claim 1 , wherein the first anode-active metal layer comprises a lithium foil having a width of at least 20 mm and a length of at least 120 mm.
22 . The anode of claim 21 , wherein the current-collector comprises copper.
23 . The anode of claim 1 , wherein the current-collector comprises a solid metal foil.
24 . The anode of claim 1 , wherein the current-collector comprises a perforated metal foil.
25 . The anode of claim 1 , wherein the current-collector comprises a metal mesh.
26 . The anode of claim 1 , wherein the current-collector has a thickness in a range of about 4 um to about 10 um.
27 . An electrochemical device comprising a cathode, an electrolyte, and an anode of claim 1 .