# US 2026/0100481 A1 · Composite separator, composite electrolyte including the same, and lithium battery including the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2026/0100481 A1 - Document ID: US20260100481A1 - Status: Published application - Kind: A1 - Application number: 19/336,693 - Filed: 2025-09-23 - Published: 2026-04-09 - Earliest claimed: 2024-10-04 - Assignees: The Industry & Academic Cooperation in Chungnam National University (IAC) - Applicants: The Industry & Academic Cooperation in Chungnam National University (IAC) - Inventors: Heesu KIM; Youngmin Moon; Sangbaek Park; Woo-Jin Song; Seung-Wan Song - Web page: https://patentgrep.com/patent/US20260100481A1 ## CPC - H01M 50/457: comprising three or more layers - H01M 10/052: Li-accumulators - H01M 10/0562: Solid materials - H01M 10/0565: Polymeric materials, e.g. gel-type or solid-type - H01M 50/423: Polyamide resins - H01M 50/426: Fluorocarbon polymers - H01M 50/446: Composite material consisting of a mixture of organic and inorganic materials - H01M 50/491: Porosity - H01M 50/497: Ionic conductivity - H01M 2300/0071: Oxides - H01M 2300/0094: in the form of layered products, e.g. coatings - Y02E 60/10: Energy storage using batteries - H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract Disclosed herein are a composite separator, a composite electrolyte including the composite separator, and a lithium battery including the composite separator, the composite separator including a first layer including an oxide-based solid electrolyte and a carbonyl group-containing a first polymer, a second layer disposed on one surface of the first layer and including a second polymer, and a third layer disposed on the other surface of the first layer and including a third polymer, wherein a content of the oxide-based solid electrolyte is 80 wt % or more with respect to a total weight of the oxide-based solid electrolyte and the first polymer. ## Claims ### Claim 1 A composite separator comprising: a first layer including an oxide-based solid electrolyte and a carbonyl group-containing first polymer; a second layer disposed on one surface of the first layer and including a second polymer; and a third layer disposed on the other surface of the first layer and including a third polymer, wherein a content of the oxide-based solid electrolyte is 80 wt % or more with respect to a total weight of the oxide-based solid electrolyte and the first polymer. ### Claim 2 (depends on 1) The composite separator of claim 1, wherein the oxide-based solid electrolyte includes an oxide-based solid electrolyte core and a coating layer disposed on a surface of the core, the coating layer includes a lithium-containing compound, and the lithium-containing compound includes lithium carbonate, lithium hydroxide, or a combination thereof. ### Claim 3 (depends on 2) The composite separator of claim 2, wherein the coating layer is disposed between the oxide-based solid electrolyte core and the first polymer, and the coating layer is a conformal coating layer disposed along a contour of the surface of the oxide-based solid electrolyte core. ### Claim 4 (depends on 2) The composite separator of claim 2, wherein, in XPS depth profile measurement of the surface of the oxide-based solid electrolyte, a second oxygen peak derived from lattice oxygen (Olattice) of the oxide-based solid electrolyte at about 527.5 eV to about 530 eV is absent when sputtering begins, and a ratio (P2/P1) of an intensity (P1) of a first oxygen peak derived from lithium carbonate (Li2CO3) at a binding energy of about 530 eV to about 532.5 eV and an intensity (P2) of the second oxygen peak derived from lattice oxygen (Olattice) of the oxide-based solid electrolyte at a binding energy of about 527.5 eV to about 530 eV is 1 or less at 130 seconds after sputtering begins. ### Claim 5 (depends on 2) The composite separator of claim 2, wherein the coating layer has a thickness of about 3 nm to about 100 nm. ### Claim 6 (depends on 1) The composite separator of claim 1, wherein the oxide-based solid electrolyte is an oxide or phosphate including lithium and two or more metals other than lithium, the oxide-based solid electrolyte includes a Garnet-type solid electrolyte, a Nasicon-type solid electrolyte, a LISICON-type solid electrolyte, a perovskite-type solid electrolyte, a LiPON-type solid electrolyte, an amorphous solid electrolyte, or a combination thereof, the oxide-based solid electrolyte includes a lithium-lanthanum-zirconium-oxide (LLZO), a lithium-aluminum-titanium-phosphate (LATP), a lithium-lanthanum-titanium-oxide (LLTO), a lithium-aluminum-germanium-phosphate (LAGP), or a combination thereof, and a content of lithium per mol of the lithium-lanthanum-zirconium-oxide is 6.8 mol or more. ### Claim 7 (depends on 1) The composite separator of claim 1, wherein the oxide-based solid electrolyte includes a garnet-type oxide, the garnet-type oxide includes a cubic phase, and the garnet-type oxide is represented by Formula 1 below: wherein in Formula 1, M1 is H, Fe, Ga, Al, B, Be, or a combination thereof, M2 is Ba, Ca, Sr, Y, Bi, Pr, Nd, Ac, Sm, Gd, or a combination thereof, M3 is Al, Ga, Ta, Nb, Hf, Ti, V, Cr, Co, Ni, Cu, Mo, W, Mg, Tc, Pd, Sc, Cd, In, Sb, Te, TI, Pt, Si, Ir, Ru, Mn, Sn, or a combination thereof, and 6≤a≤8, 0≤b≤2, 2.5≤c≤3.5, 0≤d≤0.2, 1.5≤e≤2.5, and 0≤f≤1. ### Claim 8 (depends on 1) The composite separator of claim 1, wherein the first polymer includes an ester group-containing polymer, an amide group-containing polymer, or a combination thereof, and the first polymer is a non-fluorinated polymer. ### Claim 9 (depends on 1) The composite separator of claim 1, wherein the first polymer includes an acetate polymer, an acrylic polymer, a urethane polymer, or a combination thereof, and the first polymer includes ethylene-vinyl acetate (EVA), polyvinyl acetate (PVAc), polyurethane (PU), polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), or a combination thereof. ### Claim 10 (depends on 1) The composite separator of claim 1, wherein the first polymer has a thermal decomposition temperature of 300° C. or higher during TGA thermal analysis. ### Claim 11 (depends on 1) The composite separator of claim 1, wherein the first layer includes an ion-conductive composite film, the ion-conductive film is a free-standing film, and the composite separator is a stretchable free-standing film or a flexible free-standing film. ### Claim 12 (depends on 1) The composite separator of claim 1, wherein the second layer and the third layer are each independently a porous layer, the second polymer and the third polymer each independently include a fluorine-based polymer, and the fluorine-based polymer includes polyvinylidene fluoride (PVDF), a polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), polytetrafluoroethylene (PTFE), or a combination thereof. ### Claim 13 (depends on 1) The composite separator of claim 1, wherein the second layer and the third layer are each independently an organic layer, and the second layer and the third layer are free of inorganic particles. ### Claim 14 (depends on 1) The composite separator of claim 1, wherein a ratio (T2/T1) of a thickness (T2) of the second layer to a thickness (T1) of the first layer is about 0.01 to about 100, a ratio (T3/T1) of a thickness of the third layer (T3) to a thickness of the first layer (T1) is about 0.01 to about 100, the first layer has a thickness of about 10 μm to about 100 μm, and the second layer or the third layer has a thickness of about 1 μm to about 100 μm. ### Claim 15 (depends on 1) The composite separator of claim 1, wherein the first layer has a porosity of less than 30%, the second layer or the third layer has a porosity of more than 30%, the composite separator has a porosity of 40% or less, and the composite separator has an electrolyte uptake of 130% or less. ### Claim 16 (depends on 1) The composite separator of claim 1, wherein the composite separator has an ionic conductivity of 0.2 mS/cm or more at 25° C. and 1 atm, the composite separator has an effective ionic conductivity of 0.25 mS/cm or more at 25° C. and 1 atm, the composite separator has a lithium ion transference number of 0.5 or more, and the composite separator has an electrochemical stability voltage window of 4.7 V (vs. Li) or more and has an oxidation current of 10 μA or less. ### Claim 17 (depends on 1) The composite separator of claim 1, wherein the composite separator has a thermal shrinkage rate of 3% or less after exposure at 180° C. for 20 minutes. ### Claim 18 (depends on 1) The composite separator of claim 1, wherein the composite separator is self-extinguishing. ### Claim 19 (depends on 1) A composite electrolyte comprising: the composite separator of claim 1; and an electrolyte disposed in the composite separator. ### Claim 20 (depends on 1) A lithium battery comprising: a cathode; an anode; and the composite separator of claim 1 between the cathode and the anode.