DENSE ELECTRODE FOR SOLID STATE BATTERY
A method for producing a cathode membrane for use in a lithium ion battery using milling and sintering. The cathode membrane is comparatively dense. The cathode membrane can be formed by a composition of active materials and inorganic lithium ion conductors. Conductive additives can be included in the cathode composition. A conducting coating can be applied to a surface of the cathode membrane.
1 . A cathode comprising:
a membrane comprising fused particles of an electrochemically active material and a sintering product, wherein the particles of the electrochemically active material are fused via the sintering product;
wherein the membrane is characterized by a porosity of no greater than 30% and the electrochemically active material comprises at least about 92% of the total weight of the membrane.
2 . The cathode of claim 1 wherein the electrochemically active material comprises a layered oxide.
3 . The cathode of claim 1 wherein the electrochemically active material comprises LiNi x Mn y Co z O w , where 0≤x<1; 0≤y<1; 0≤z≤1; and 1.8≤w≤2.2.
4 . (canceled)
5 . The cathode of claim 1 wherein the sintering product comprises unreacted sintering aid, reacted sintering aid, decomposed sintering aid, and combinations thereof.
6 . The cathode of claim 5 wherein the sintering aid is selected from the group consisting of Li 3 BO 3 , Li 2 O, LiF, LiBO 2 and combinations thereof.
7 . The cathode of claim 5 wherein the sintering aid comprises a combination of Li 2 O and LiBO 2 .
8 . The cathode of claim 5 wherein the sintering aid comprises a combination of LiF and LiBO 2 .
9 . The cathode of claim 1 further comprising an electron-conducting additive.
10 . The cathode of claim 9 wherein the electron-conducting additive is selected from the group consisting of IrO 2 , ReO 2 , and TiN.
11 . The cathode of claim 1 further comprising a conductive coating deposited on a surface of the membrane.
12 . The cathode of claim 11 wherein the conductive coating comprises gold or conductive carbon.
13 . The cathode of claim 1 wherein the membrane is characterized by a porosity of no greater than 15%.
14 . The cathode of claim 1 wherein the membrane is characterized by a porosity of no greater than 10%.
15 . The cathode of claim 1 wherein the membrane is characterized by a porosity of no greater than 5%.
16 . The cathode of claim 1 wherein the membrane is characterized by a porosity of no greater than 1%.
17 . A method for forming a cathode membrane, comprising:
preparing a solution comprising a binder and a solvent;
milling an electrochemically active material and a sintering aid to form a milled material;
mixing the solution and the milled material to form a mixture;
casting the mixture to form a film of a desired thickness; and
sintering the film to form the cathode membrane wherein the cathode membrane comprises fused particles of electrochemically active material and the membrane is characterized by a porosity of no greater than about 15%.
18 . The method of claim 17 further comprising milling an inorganic electron-conducting additive with the electrochemically active material and the sintering aid.
19 . The method of claim 17 further comprising forming a conductive coating on a surface of the cathode membrane.
20 . The method of claim 17 wherein the electrochemically active material comprises a layered oxide.
21 . (canceled)
22 . The method of claim 17 wherein the sintering aid is selected from the group consisting of Li 3 BO 3 , Li 2 O, LiF, LiBO 2 and combinations thereof.