Lithium air battery having multi-layered electrolyte membrane and manufacturing method thereof
Disclosed herein are a lithium air battery having a multi-layered electrolyte membrane and a method of manufacturing the same. The lithium air battery includes a first electrolyte membrane capable of obtaining high ionic conductivity on a lithium negative electrode surface while minimizing the content of polymer and positioning a second electrolyte membrane with high resistance to oxygen radicals on the air electrode. Accordingly, the multi-layered electrolyte membrane can improve an electrolyte filling characteristic and a conductive characteristic of lithium ions, suppress oxygen radicals from being carried from an air electrode, and suppress a growth of lithium dendrite to largely improve a battery lifespan.
1. A method of manufacturing a lithium air battery, comprising:
(a) preparing a first electrolyte membrane by mixing a lithium ion conductive inorganic electrolyte, a polymer electrolyte, and a pore-forming additive with an organic solvent;
(b) preparing a second electrolyte membrane;
(c) laminating the second electrolyte membrane on the first electrolyte membrane;
(d) soaking the laminated first and second electrolyte membranes in a liquid electrolyte;
(e) forming a lithium negative electrode on the first electrolyte membrane prepared in step (d); and
(f) forming an air electrode on the second electrolyte membrane prepared in step (d),
wherein the lithium ion conductive inorganic electrolyte and the polymer electrolyte are mixed in a weight ratio of about 80 to 90:10 to 20 to prepare the first electrolyte membrane,
wherein the pore-forming additive is dibutylphthalate, and
wherein an amount of about 5 to 10 wt % of the pore-forming additive is mixed with respect to the total weight combining the lithium ion conductive inorganic electrolyte and the polymer electrolyte.
2. The method of claim 1 , wherein the lithium ion conductive inorganic electrolyte is at least one selected from the group consisting of oxide, phosphate, sulfide, and LiPON-based inorganic materials.
3. The method of claim 1 , wherein the first electrolyte membrane comprises pores having an average pore size of about 0.01 to 10 μm and porosity of about 20 to 30%.
4. The method of claim 1 , wherein the first electrolyte membrane has a thickness of about 20 to 80 μm and the second electrolyte membrane has a thickness of about 200 to 300 μm.
5. The method of claim 1 , wherein the second electrolyte membrane is at least one kind selected from the group consisting of a glass fiber, an olefin-based resin, a fluorine-based resin, an ester-based resin, and a cellulose-based non-woven fabric.