Preparation and application of a polyrotaxane-based polymer electrolyte

Patent metadata

Field	Value
Publication number	US-12482859-B2
Application number	US-202318833895-A
Country	US
Kind code	B2
Filing date	Oct 31, 2023
Priority date	Dec 29, 2022
Publication date	Nov 25, 2025
Grant date	Nov 25, 2025

Abstract

The invention discloses A preparation method of polyrotaxane polymer electrolyte and its application, and belongs to the technical field of lithium ion batteries. The polyrotaxane polymer is composed of a linear polymer, a cyclic molecule and an end-capping molecule. The polyrotaxane polymer electrolyte is composed of a polyrotaxane polymer, a conductive lithium salt and a porous support material. The polymer electrolyte is simple in preparation process, free of byproducts and excellent in electrochemical performance. The room-temperature ionic conductivity can be greater than 10−3 Scm−1, and the electrochemical window can be greater than 5V (vs.Li+/Li); and the lithium metal battery assembled by the composite material has excellent cycle performance at room temperature. The interfacial compatibility of the polymer electrolyte and the electrode can be obviously improved, so that the electrochemical performance and the safety performance of the battery are improved.

First claim

What is claimed is:

1 . A polyrotaxane lithium-ion battery polymer electrolyte, characterized in that the polymer electrolyte comprises a polyrotaxane polymer and a conductive lithium salt;
the polyrotaxane lithium-ion battery polymer electrolyte is prepared from a linear polymer, a cyclic molecule, an end-capping molecule, a catalyst, and a lithium salt, wherein the linear polymer, the cyclic molecule, and the end capping molecule form the polyrotaxane polymer; a molar ratio of the linear polymer, the cyclic molecule, and the end-capping molecule is 1:(0.1-10):(0.1-10); wherein the catalyst is present at 0.1%-10% by mass based mass of the linear polymer, and the lithium salt is present at 10%-80% by mass based on the mass of the linear polymer; the polyrotaxane lithium-ion battery polymer electrolyte uses a porous support material as a carrier; the linear polymer is selected from polyethylene glycol, polyvinyl alcohol, polypropylene glycol, or one or more of the sulfur, chlorine or fluorine substitutes of polyethylene glycol, polyvinyl alcohol and polypropylene glycol; a molecular weight of the linear polymer is in the range of 1000-1000000 g/mol; the cyclic molecule is selected from one or more of crown ether group molecules and cyclodextrin group molecules; the end-capping molecule is one or more of the following: hexamethylene diisocyanate (HDI), hexamethylene diisocyanate trimer (HDI trimer), diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), (polymethyl polyphenyl isocyanate) (PAPI), (phenyl isocyanate) (PI), (isophorone diisocyanate) (IPDI), (octadecyl isocyanate) (ODI), dicyclohexylmethane diisocyanate (HMDI), lysine diisocyanate (LDI); a molecular weight of the end-capping molecule is in the range of 100-10000 g/mol; the conductive lithium salt is one or more of the following: lithium hexafluorophosphate (LiPF 6 ), lithium perchlorate (LiClO 4 ), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(oxalatoborate) (LiBOB), bis(trifluoromethanesulfonyl)methyl lithium (LiC(SO 2 CF 3 ) 3 ), lithium difluorooxalatoborate (LiDFOB); and the catalyst is one of the following: dibutyltin dilaurate, dibutyltin bis(acetylacetonate), azobisisoheptanenitrile (ABVN), azobisisobutyronitrile (AIBN), dimethyl azobisisobutyrate (AIBME), benzoyl peroxide (BPO), tert-butyl benzoyl peroxide (TBPB), methyl ethyl ketone peroxide (MEKPO).

2 . The polyrotaxane lithium-ion battery polymer electrolyte according to claim 1 , characterized in that the molecular weight of the linear polymer is in the range of 1000-1000000 g/mol.

3 . The polyrotaxane lithium-ion battery polymer electrolyte according to claim 1 , characterized in that the crown ether group molecule is selected from one or more of 18-crown ether-6, dibenzo-18 crown ether-6, 18-diaza crown ether-6, dibenzo-18-tetrathio crown ether-6, tetrabenzo-18-crown ether-6, cyclohexane-18-crown-6, 21-crown ether-7, and 24-crown ether-8, and the cyclodextrin type group molecule is α, β or γ type cyclodextrin, or a reaction product of etherification, esterification, oxidation, cross-linking, etc. of alcoholic hydroxyl groups on the surface of cyclodextrin, or one or more of chlorine and fluorine substituents of cyclodextrin.

4 . The polyrotaxane lithium-ion battery polymer electrolyte according to claim 1 , characterized in that the porous supporting material is one or more of the following: cellulose non-woven fabric, polyethylene non-woven fabric, polypropylene non-woven fabric, glass fiber non-woven fabric, polytetrafluoroethylene non-woven fabric.

5 . The method for preparing the polyrotaxane-based lithium-ion battery polymer electrolyte according to claim 1 , characterized in that it comprises the following steps:
1) dissolving the linear polymer and the cyclic molecule in a liquid solvent and stirring for 2-10 hours to allow the linear polymer to pass through the cyclic molecule, thereby forming a solution; 2) adding one or more end-capping molecules and a catalyst to the solution and continuing to stir for 2-10 hours to obtain a polyrotaxane polymer solution; 3) adding a certain amount of lithium salt to the polyrotaxane polymer solution to form a uniform solution, thereby obtaining a polyrotaxane polymer electrolyte mixed solution; and 4) The polyrotaxane polymer electrolyte mixed solution is coated on or immersed in a porous support material, and then cured by vacuum heating at 60-120° C. for 2-12 h to obtain a fully solid polymer electrolyte membrane.

6 . The method according to claim 5 , characterized in that the solvent is one of the following: N-methylpyrrolidone, ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, ethyl methyl carbonate, γ-butyrolactone, tetrahydrofuran, 2-methyltetrahydrofuran, acetonitrile, 1,2-dimethoxyethane, tetraethylene glycol dimethyl ether, triethylene glycol dimethyl ether, diethylene glycol dimethyl ether, and dimethyl sulfoxide.

7 . A polymer-based lithium-ion battery with a polyrotaxane-based lithium-ion battery polymer electrolyte, characterized in that it comprises: a positive electrode, a negative electrode, and the polyrotaxane-based lithium-ion battery polymer electrolyte as described in claim 1 , which is placed between the positive electrode and the negative electrode and has both the functions of a separator and an electrolyte.

8 . The lithium-ion battery according to claim 7 , characterized in that the positive electrode active material is one or more of lithium iron phosphate, lithium nickel cobalt aluminum (NCA), lithium-rich material (LLOs), lithium cobalt oxide (LiCoO 2 ), lithium fluorophosphate, lithium nickel cobalt manganese oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium iron manganese phosphate, and lithium nickel oxide (LiNiO 2 ); and the negative electrode active material is one or more of metallic lithium, metallic lithium alloy, carbon silicon composite material, lithium titanate, graphite, lithium metal nitride, antimony oxide, carbon germanium composite material, and lithium titanium oxide.

9 . The lithium-ion battery according to claim 8 is characterized in that preparing the positive electrode comprises the following steps:
(1) preparing a positive electrode material by grinding and mixing 50-90% by mass of the positive electrode active material and 5-30% by mass of a conductive agent acetylene black, adding 1-15% by mass of polyvinylidene fluoride (PVDF), 1-15% of the polyrotaxane polymer electrolyte, and 1-methyl-2-pyrrolidone to obtain the positive electrode material, wherein the 1-methyl-2-pyrrolidone is used to adjust a viscosity and is not included in a mass percentage composition of the positive electrode material; and
(2) coating the positive electrode material on a surface of aluminum foil and vacuum drying to obtain the positive electrode; wherein
metallic lithium or metallic lithium alloy is directly used as a corresponding negative electrode; or preparing the negative electrode includes the following steps:
(1) preparing a negative electrode material by grinding and mixing 35-85% by mass of the negative electrode active material and 5-30% by mass of a conductive agent acetylene black, adding 5-20% by mass of polyvinylidene fluoride (PVDF), 1-20% of the polyrotaxane polymer electrolyte and 1-methyl-2-pyrrolidone, grinding and mixing to obtain the negative electrode material; wherein the 1-methyl-2-pyrrolidone is used to adjust a viscosity and is not included in the mass percentage composition of the negative electrode material; and
(2) coating the negative electrode material on a surface of copper foil and drying to obtain the negative electrode;
wherein the polyrotaxane polymer electrolyte in

Assignees

• Univ Beijing Technology

Inventors

• Yu Haijun
• Wu Lingqiao
• Ding Peipei
• Guo Xianwei

Classifications

• H01M2300/0085

  Immobilising or gelification of electrolyte · CPC title

• H01M2300/0082

  Organic polymers · CPC title

• H01M2004/028

  Positive electrodes · CPC title

• H01M2004/027

  Negative electrodes · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title