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CN-121238157-B - Composite solid electrolyte diaphragm and preparation method thereof

CN121238157BCN 121238157 BCN121238157 BCN 121238157BCN-121238157-B

Abstract

The invention provides a composite solid electrolyte membrane and a preparation method thereof, and relates to the technical field of lithium batteries. The flame-retardant PVC composite material comprises, by weight, 15-25 parts of flame-retardant microcapsules, a core-shell structure, EDTA modified LATP nanoparticles as a shell, an expansion monomer as a core, 20-30 parts of amino modified carbon nitride, 60-80 parts of bacterial cellulose films and 40-60 parts of polyethylene oxide particles. The composite electrolyte membrane has high thermal stability and dimensional stability, and each component on the microstructure is uniformly deposited to form a continuous phase, so that a rapid channel is provided for ion migration and conduction, and the performance and safety of the battery are remarkably improved.

Inventors

  • LI YANHONG

Assignees

  • 星恒电源(滁州)有限公司
  • 星恒电源股份有限公司

Dates

Publication Date
20260505
Application Date
20251031

Claims (9)

  1. 1. The composite solid electrolyte membrane is characterized by comprising the following components in parts by weight: 15-25 parts of flame-retardant microcapsules, wherein the flame-retardant microcapsules are of a core-shell structure, the shell is EDTA modified LATP nano particles, and the core is an expansion monomer; 20-30 parts of amino modified carbon nitride; 60-80 parts of bacterial cellulose film; 40-60 parts of polyethylene oxide particles.
  2. 2. The composite solid electrolyte membrane of claim 1 wherein the swelling monomer is 3, 9-diethyl-3, 9-dihydroxymethyl-1,5,7,11-tetraoxaspiro (5, 5) undecane and/or, The flame retardant microcapsule also comprises azodiisobutyronitrile.
  3. 3. The composite solid electrolyte membrane of claim 2, wherein the flame retardant microcapsule comprises the following components in parts by weight: 50-65 parts of EDTA modified LATP nano particles; 30-45 parts of 3, 9-diethyl-3, 9-dihydroxymethyl-1,5,7,11-tetraoxaspiro (5, 5) undecane; 12.2-15.7 parts of azodiisobutyronitrile.
  4. 4. A method of preparing the composite solid electrolyte membrane of any one of claims 1-3, comprising: Dispersing flame-retardant microcapsules, amino-modified carbon nitride and polyethylene oxide particles in an organic solvent to form a dispersion liquid; immersing a bacterial cellulose membrane in the dispersion liquid, and diffusing particles in the dispersion liquid into the bacterial cellulose membrane to obtain a composite wet membrane; And removing the solvent from the composite wet film, and performing rolling pressing treatment to obtain the composite solid electrolyte membrane.
  5. 5. The method for preparing a composite solid electrolyte membrane according to claim 4, wherein immersing the bacterial cellulose membrane in the dispersion liquid, and diffusing particles in the dispersion liquid into the bacterial cellulose membrane, to obtain a composite wet membrane, comprises: And diffusing particles in the dispersion liquid into the bacterial cellulose membrane by an ultrasonic auxiliary treatment mode to obtain the composite wet membrane.
  6. 6. The method for preparing a composite solid electrolyte membrane according to claim 4, wherein the solvent removal method of the composite wet membrane is to remove the solvent in the composite wet membrane by a decompression method.
  7. 7. The method for preparing a composite solid electrolyte membrane according to claim 4, wherein the method for preparing the flame retardant microcapsule comprises: preparing EDTA modified LATP nano particles, and preparing aqueous phase solution by using the EDTA modified LATP nano particles; preparing an oil phase solution by DHOM and AIBN; Mixing the aqueous phase solution and the oil phase solution to form an oil-in-water emulsion; And after the reaction is finished, drying under reduced pressure, separating solid from liquid, washing, drying and screening to obtain the flame-retardant microcapsule.
  8. 8. A battery comprising a positive electrode, a negative electrode, and an electrolyte, and the composite solid electrolyte separator according to any one of claims 1 to 3.
  9. 9. An electrical device comprising the battery of claim 8.

Description

Composite solid electrolyte diaphragm and preparation method thereof Technical Field The invention relates to the technical field of lithium batteries, in particular to a composite solid electrolyte membrane and a preparation method thereof. Background In modern energy storage technology, lithium ion batteries are widely used as efficient and chargeable energy storage devices in various fields from portable electronic devices to electric automobiles. The electrolyte is used as a key component of the lithium ion battery and is responsible for conducting lithium ions in the battery, and plays a vital role in the performance, safety and service life of the battery. Solid state electrolytes are becoming a hotspot in lithium ion battery technology research due to their advantages in terms of safety, shape flexibility, and potentially high energy density. The solid electrolyte can provide a stable ion conduction path in the battery, and meanwhile, potential safety hazards such as leakage and combustion and the like possibly caused by the traditional liquid electrolyte are avoided, so that the solid electrolyte is considered to have a wide application prospect. Existing solid electrolytes are mainly divided into two major classes, namely inorganic solid electrolytes and organic polymer solid electrolytes. Inorganic solid electrolytes, such as Lithium Aluminum Titanium Phosphate (LATP), have been attracting attention for their excellent ionic conductivity and lithium ion transport number. The high mechanical properties of this material allow for good stability in the cell structure. However, the inorganic solid electrolyte has obvious defects that the interface wettability with the electrode is poor, so that the interface contact resistance is high, the charge and discharge speed of the battery is limited, the problems of local overheating and the like in the battery can be caused, and the overall performance and the safety of the battery are influenced. On the other hand, organic polymer solid electrolytes have been attracting attention due to their soft and lightweight properties, and among them, polyethylene oxide (PEO) electrolytes are one of the most widely studied solid electrolytes due to their excellent interfacial contact and ease of handling. The softness and lightweight nature of PEO electrolytes provides greater flexibility in cell design, with good interfacial contact properties helping to reduce the internal resistance of the cell. However, at room temperature, PEO electrolytes often exhibit semi-crystalline states, which lead to problems of low ionic conductivity and insufficient migration number of lithium ions, limiting their use in high performance batteries. Although organic/inorganic composite solid state electrolytes combine the advantages of inorganic and polymer electrolytes and overcome each other's drawbacks, are considered one of the most promising options for commercial applications, many challenges remain in the practical manufacturing process. On the one hand, the problem of compatibility between the inorganic filler and the polymer matrix may lead to insufficient uniformity of the composite material and influence the ion conductivity, and on the other hand, the preparation process of the composite electrolyte is complex, the cost is high, and the mass production is difficult to realize. These problems limit the wide use of composite solid electrolytes in lithium ion batteries. Therefore, how to prepare a composite solid electrolyte with excellent comprehensive performance and low cost, which is suitable for mass production, becomes a key problem in the current technical development of lithium ion batteries. Disclosure of Invention The invention aims to provide a composite solid electrolyte membrane and a preparation method thereof. The composite electrolyte membrane has high thermal stability and dimensional stability, and each component on the microstructure is uniformly deposited to form a continuous phase, so that a rapid channel is provided for ion migration and conduction, and the performance and safety of the battery are remarkably improved. In order to achieve the above object of the present invention, the following technical solutions are specifically adopted: in a first aspect, the application provides a composite solid electrolyte membrane, which comprises the following components in parts by weight: 15-25 parts of flame-retardant microcapsules, wherein the flame-retardant microcapsules are of a core-shell structure, the shell is EDTA modified LATP nano particles, and the core is an expansion monomer; 20-30 parts of amino modified carbon nitride; 60-80 parts of bacterial cellulose film; 40-60 parts of polyethylene oxide particles. In a preferred embodiment, the swelling monomer is 3, 9-diethyl-3, 9-dihydroxymethyl-1,5,7,11-tetraoxaspiro (5, 5) undecane, and/or, The flame retardant microcapsule also comprises azodiisobutyronitrile. In a preferred embodiment, the flame retardan