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CN-122025759-A - Hydrophobic sulfide electrolyte membrane and preparation method and application thereof

CN122025759ACN 122025759 ACN122025759 ACN 122025759ACN-122025759-A

Abstract

The invention belongs to the field of solid batteries, and relates to a hydrophobic sulfide electrolyte membrane, a preparation method and application thereof, wherein the hydrophobic sulfide electrolyte membrane comprises a sulfide electrolyte base membrane and a F-POS@oxide composite hydrophobic coating coated on the surface of the sulfide electrolyte base membrane, the water static contact angle of the hydrophobic sulfide electrolyte membrane is more than 160 degrees, the ion conductivity is more than 6.0 mS/cm, the water static contact angle of the hydrophobic sulfide electrolyte membrane is more than 160 degrees, and the ion conductivity is more than 6.0 mS/cm. The F-POS@oxide composite coating realizes super-hydrophobic property, and simultaneously maintains high ionic conductivity, so that the problems of toxic gas release and sudden drop of ionic conductivity caused by hydrolysis of the traditional sulfide electrolyte when meeting water are solved.

Inventors

  • WANG YIFEI
  • QIN DAN
  • CHEN BAOTIAN
  • SUN WEI
  • FU YUE
  • YANG YIWEN
  • YE HUI

Assignees

  • 合肥国轩高科动力能源有限公司

Dates

Publication Date
20260512
Application Date
20260204

Claims (10)

  1. 1. The hydrophobic sulfide electrolyte membrane is characterized by comprising a sulfide electrolyte base membrane and a F-POS@oxide composite hydrophobic coating coated on the surface of the sulfide electrolyte base membrane, wherein the water static contact angle of the hydrophobic sulfide electrolyte membrane is more than 160 degrees, and the ionic conductivity of the hydrophobic sulfide electrolyte membrane is more than 6.0 mS/cm.
  2. 2. The hydrophobic sulfide electrolyte membrane according to claim 1, wherein the sulfide electrolyte base membrane is made of a mixture of a sulfide electrolyte and a fluorine-containing polymer binder in a mass ratio of 90 to 100:1, and the sulfide electrolyte base membrane has a thickness of 80 to 200 μm.
  3. 3. The hydrophobic sulfide electrolyte membrane according to claim 1, wherein the F-pos@oxide composite hydrophobic coating is formed by curing F-pos@oxide nanoparticles, wherein the F-pos@oxide nanoparticles are obtained by hydrolytic condensation modification of lithium ion conductive oxide nanoparticles with alkylsilanes and fluoroalkylsilanes, the thickness of the F-pos@oxide composite hydrophobic coating is 5-20 μm, and the D50 of the lithium ion conductive oxide nanoparticles is 10-300nm.
  4. 4. The hydrophobic sulfide electrolyte membrane according to claim 3, wherein the volume ratio of the alkylsilane to the fluoroalkylsilane is (2-4): 1.
  5. 5. The hydrophobic sulfide electrolyte membrane according to claim 2, wherein the sulfide electrolyte is selected from at least one of halogenated lithium sulfur phosphorus compounds, the lithium ion conductive oxide nanoparticles are selected from at least one of lithium aluminum titanate, lithium lanthanum zirconium oxygen, lithium lanthanum zirconium tantalum oxygen, lithium lanthanum zirconium aluminum oxygen, and the fluoropolymer binder is selected from at least one of polytetrafluoroethylene, polyvinylidene fluoride-hexafluoropropylene.
  6. 6. A method for producing the hydrophobic sulfide electrolyte membrane according to any one of claims 1 to 5, comprising the steps of: Step 1, preparing F-POS@oxide nano particles, namely dispersing lithium ion conductive oxide electrolyte nano particles in a mixed system of an organic solvent and ammonia water, stirring to form a uniform suspension, adding alkylsilane and fluoroalkyl silane for hydrolysis condensation reaction to obtain a suspension, centrifuging the suspension, washing and drying to obtain the F-POS@oxide nano particles; Step2, preparing a sulfide electrolyte base film, namely mixing lithium sulfide, phosphorus pentasulfide and lithium halide, preparing sulfide electrolyte through heat treatment for 4-6 hours at 500-600 ℃, mixing the sulfide electrolyte with a fluorine-containing polymer binder, and pressing to prepare the sulfide electrolyte base film; And 3, preparing a hydrophobic sulfide electrolyte membrane, namely dispersing the F-POS@oxide nano particles into a normal hexane solution to obtain a spraying liquid, spraying the spraying liquid on the surface of the sulfide electrolyte base membrane by using a spray gun in an inert atmosphere, and drying to remove residual solvent to obtain the hydrophobic sulfide electrolyte membrane.
  7. 7. The method according to claim 6, wherein in the step of preparing the fpos@oxide nanoparticles, the organic solvent is at least one selected from the group consisting of absolute ethyl alcohol, absolute propyl alcohol and absolute butyl alcohol, and the dispersion medium of the lithium ion conductive oxide nanoparticle suspension is a lower alcohol.
  8. 8. The method for producing a hydrophobic sulfide electrolyte membrane according to claim 6, wherein in the step of producing a sulfide electrolyte base film, the lithium halide is at least one selected from the group consisting of lithium chloride, lithium bromide, and lithium iodide.
  9. 9. Use of the hydrophobic sulfide electrolyte membrane according to any one of claims 1 to 5 as an electrolyte layer of an all-solid battery.
  10. 10. An all-solid battery comprising a positive electrode, a negative electrode, and an electrolyte layer between the positive electrode and the negative electrode, wherein the electrolyte layer is the hydrophobic sulfide electrolyte membrane according to any one of claims 1 to 5.

Description

Hydrophobic sulfide electrolyte membrane and preparation method and application thereof Technical Field The invention belongs to the technical field of solid-state batteries, and relates to a hydrophobic sulfide electrolyte membrane, a preparation method and application thereof. Background An all-solid battery (ASSB) is a lithium battery that uses a solid electrode material and a solid electrolyte material, and does not contain any liquid. The working principle of the lithium ion battery is the same as that of a liquid lithium ion battery, the lithium ion battery is called as a rocking chair type battery, the two ends of the rocking chair are the positive electrode and the negative electrode of the battery, and lithium ions migrate back and forth in a solid electrolyte to realize the charge and discharge process. The positive electrode material is typically a high voltage, high capacity material such as lithium iron phosphate, a lithium-rich manganese-based material, or nickel cobalt manganese oxide. The negative electrode material can be lithium metal, silicon or other high-energy density materials, and the lithium metal negative electrode is considered as the key of the development of the all-solid-state battery due to the ultrahigh theoretical specific capacity. The solid electrolyte is a core component of an all-solid battery, and is required to have high ionic conductivity, low electronic conductivity, excellent chemical and mechanical stability, and good interface compatibility. The main types are inorganic solid electrolytes, polymer electrolytes, and composite solid electrolytes. All-solid-state batteries have a high energy density, and the high mechanical strength of the solid-state electrolyte allows the use of lithium metal as the negative electrode, significantly increasing the energy density of the battery. Meanwhile, the electrolyte has higher safety, avoids the problems of leakage, combustion and thermal runaway of the liquid electrolyte, and shows better stability under high temperature or extreme conditions. The solid electrolyte can also effectively inhibit the growth of lithium dendrites and prolong the service life of the battery. In addition, the device can work in a wider temperature range, and is suitable for extreme environment application. Therefore, all-solid-state batteries have been recognized as a next-generation energy storage technology having high energy density, power density, and safety. However, all-solid batteries still face challenges such as that the ionic conductivity of many solid electrolytes is still lower than that of liquid electrolytes, and the cost of preparing high performance solid electrolyte materials, such as sulfides, is high. Among all Solid Electrolytes (SE) of all solid-state batteries (ASSB), sulfide is one of the most promising technological routes due to its high ionic conductivity and ideal mechanical deformability. However, most sulfides are inherently unstable and readily react with air/moisture to release toxic hydrogen sulfide (H 2 S) gas. Taking a common lithium sulfide-based solid electrolyte as an example, when the lithium sulfide-based solid electrolyte contacts water, hydrolysis reaction occurs to generate hydrogen sulfide (H 2 S) and corresponding hydroxide, and a reaction equation of the lithium sulfide-based solid electrolyte can be expressed as Li 2S + H2O = 2LiOH + H2 S ≡. After the sulfide solid electrolyte reacts with air/water, the crystal structure of the sulfide solid electrolyte is destroyed, and the original ordered crystal structure can have the problems of lattice distortion, defect increase and the like in the reaction process, so that the ion conduction channel in the sulfide solid electrolyte is not smooth. Disruption of the crystal structure directly affects the conductivity of lithium ions in the sulfide solid state electrolyte, resulting in a decrease in lithium ion conductivity. This results in a decrease in charge and discharge performance of the battery, an increase in internal resistance of the battery, a decrease in charge and discharge efficiency, and an influence on output voltage and capacity of the battery, ultimately affecting the overall performance and use experience of the all-solid-state battery. Disclosure of Invention The invention aims to provide a hydrophobic sulfide electrolyte membrane, a preparation method and application thereof, which realize superhydrophobicity through an F-POS@oxide composite coating, and simultaneously maintain high ion conductivity, thereby solving the problems of toxic gas release and sudden drop of ion conductivity caused by hydrolysis of the traditional sulfide electrolyte when meeting water. In a first aspect, the invention provides a hydrophobic sulfide electrolyte membrane, which comprises a sulfide electrolyte base membrane and a F-POS@oxide composite hydrophobic coating coated on the surface of the sulfide electrolyte base membrane, wherein the water static contact angl