Solid Electrolyte, Fabrication Method Thereof and Thin Film Battery Comprising the Same
The present invention relates to a solid electrolyte enables high ion conductivity, excellent voltage stability, low electric conductivity, homogeneous composition, reduced self-discharge and excellent atmosphere stability, a method of producing the same and a thin film battery comprising the same. The solid electrolyte according to the present invention is represented by the following formula. Li x —B—O y —N z <Formula>
1 . A solid electrolyte represented by the following formula:
Li x -B-O y —N z <Formula>
wherein 1.1<x<3.6, 0.6<y<3.1, 0.5<z<1, and 2.2<x+y+z<7.7 are in the formula.
2 . The solid electrolyte according to claim 1 , wherein 2.5<x<3.5, and 2.5<y+z<4.0 are in the formula.
3 . A method of producing a solid electrolyte, the method comprising:
providing a target comprising Li, B, and O;
depositing the target on a substrate under an atmosphere comprising nitrogen by using a vacuum deposition to form the solid electrolyte represented by the following formula:
Li x -B-O y —N z <Formula>
wherein 1.1<x<3.6, 0.6<y<3.1, 0.5<z<1, and 2.2<x+y+z<7.7 are in the formula.
4 . The method according to claim 3 , wherein the target is any one selected from the group consisting of LiBO 2 , LiBO 3 and Li 5 BO 4 .
5 . The method according to claim 4 , wherein the target is produced by providing a mixed powder that comprises a boron oxide-based powder and a lithium carbonate-based powder, sintering the mixed powder at a temperature in the range of 500 to 700° C. for 30 min to 1.5 hour, and making the sintered mixed powder by a dry mechanical working.
6 . The method according to claim 3 , wherein the atmosphere comprising nitrogen is any one selected from the group consisting of atmospheres comprising 100% of nitrogen, nitrogen and oxygen, nitrogen and argon, and nitrogen, oxygen and argon.
7 . The method according to claim 3 , wherein the vacuum deposition is any one selected from the group consisting of sputtering, ion plating, activated reactive evaporation (ARE), ion beam assisted deposition (IBAD), ionized cluster beam deposition (ICB), pulsed laser deposition (PLD) and arc source deposition.
8 . The method according to claim 7 , wherein the sputtering is performed under the power in the range of 2.0 to 4.0 W/cm 2 , and the process pressure in the range of 3.0 to 15.0 mTorr.
9 . A thin film battery comprising:
a substrate;
a cathode current collector that is positioned on the substrate;
a cathode that is positioned on the cathode current collector;
a solid electrolyte that is positioned on the cathode and is represented by the following formula;
an anode current collector that is electrically insulated with the cathode current collector; and
an anode that is positioned on the anode current collector:
Li x -B-O y —N z <Formula>
wherein 1.1<x<3.6, 0.6<y<3.1, 0.5<z<1, and 2.2<x+y+z<7.7 are in the formula.
10 . The thin film battery according to claim 9 , wherein the substrate is any one selected from the group consisting of mica, Al 2 O 3 , Si wafer, SiO 2 wafer, glass, polymer film and metal.
11 . The thin film battery according to claim 9 , wherein the cathode is any one selected from the group consisting of LiCoO 2 , LiMn 2 O 4 , Li[Ni,Co,Mn]O 2 and LiFePO 4 .
12 . The thin film battery according to claim 9 , wherein a thickness of the solid electrolyte is in the range of 0.7 to 3.0 μm.
13 . The thin film battery according to claim 9 , wherein the anode is any one selected from the group consisting of Li, C, graphite, metal oxide, nitrogen-based metal, silicide-based metal and a metal alloy thereof.