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CN-122025748-A - Preparation method of composite solid electrolyte

CN122025748ACN 122025748 ACN122025748 ACN 122025748ACN-122025748-A

Abstract

The invention discloses a preparation method of a composite solid electrolyte, which comprises the following steps of porous gamma-Al 2 O 3 skeleton pretreatment, hybrid slurry preparation, impregnation loading and preforming, ultraviolet crosslinking and low-temperature solidification. The gamma-Al 2 O 3 is taken as a framework, so that the density of the solid electrolyte is more than or equal to 95%, the Young modulus is improved to more than 8.5GPa, the stress dispersion rate is improved by 60%, microcracks and structural collapse are avoided in electric circulation, the structure is more stable, and the double functions of APTES modification and cross-linking of the PBO organic film are matched, so that the interface performance is greatly optimized, the interface impedance is controlled below 200 omega, the ion transmission efficiency is improved, and the gamma-Al 2 O 3 with lower cost is adopted to replace part of high-price Li 3 InCl 6 , so that the production cost is effectively reduced.

Inventors

  • SONG HONGFANG
  • BAI YU
  • CHEN YUHUI
  • ZHAO DONGHUI

Assignees

  • 上海市翔丰华科技股份有限公司

Dates

Publication Date
20260512
Application Date
20260305

Claims (5)

  1. 1. A preparation method of a composite solid electrolyte is characterized by comprising the following steps: (1) The porous gamma-Al 2 O 3 skeleton pretreatment, namely placing the gamma-Al 2 O 3 porous skeleton into absolute ethyl alcohol for ultrasonic cleaning for 30 minutes, then taking out and transferring the porous skeleton to a vacuum drying oven, vacuum drying the porous skeleton for 2 hours at 120 ℃, cooling the porous skeleton to room temperature, immersing the porous skeleton into an alcohol solution of APTES, wherein the concentration of the APTES is 5wt%, and the porous skeleton is subjected to constant temperature modification at 60 ℃ for 1.5-2 hours, so that the surface of the porous skeleton is grafted with amino groups, then washing the porous skeleton with the absolute ethyl alcohol for 3 times, placing the porous skeleton in the vacuum drying oven, and vacuum drying the porous skeleton at 80 ℃ for 1 hour to obtain the modified porous Al 2 O 3 skeleton; (2) The preparation of the hybridized slurry comprises the steps of placing Li 3 InCl 6 powder in a glove box, ball-milling Li 3 InCl 6 powder by adopting a high-energy ball-milling tank at the speed of 400-600r/min for 30min, adding a cross-linking agent into a DMF solution of PBO, wherein the concentration of PBO is 10wt%, the mass of PBO is 5% of that of PBO, stirring uniformly to form an organic matrix solution, mixing the ball-milled Li 3 InCl 6 with LiTFSI, the mass ratio of the ball-milled Li 3 InCl 6 to LiTFSI is (6.5-7) 1, adding the organic matrix solution, the mass ratio of the ball-milled Li 3 InCl 6 to the organic matrix solution is (6.5-7) 20-25, dispersing for 40min in the glove box by ultrasonic, and magnetically stirring for 1h to obtain the hybridized slurry; (3) Impregnating and preforming, namely placing the modified porous Al 2 O 3 skeleton obtained in the step (1) into a vacuum impregnating device, vacuumizing to-0.095 MPa and keeping for 30min, breaking bubbles in the skeleton pores, then injecting the hybridization slurry obtained in the step (2) into the vacuum impregnating device, wherein the mass ratio of the modified porous Al 2 O 3 skeleton to the hybridization slurry is (4-5) (15-16), recovering normal pressure, then applying 0.5MPa pressure to enable the hybridization slurry to fully infiltrate into the pores of the modified porous Al 2 O 3 skeleton, impregnating for 1.5-2h, and removing redundant slurry on the surface of the skeleton by using a scraper to obtain a primary blank; (4) And (3) ultraviolet crosslinking and low-temperature curing, namely placing the primary blank obtained in the step (3) into an ultraviolet curing machine, irradiating for 18-20min under ultraviolet light with the wavelength of 365nm and the power of 500W to complete the crosslinking of PBO, then preserving heat for 2h under the inert atmosphere at the temperature of 110-120 ℃, removing residual solvent, and naturally cooling to room temperature to obtain the composite solid electrolyte.
  2. 2. The method according to claim 1, wherein in the step (1), the pore diameter of the gamma-Al 2 O 3 porous skeleton is 30nm and the porosity thereof is 35%.
  3. 3. The method according to claim 1, wherein in the step (2), the water oxygen content in the glove box is not more than 0.1ppm.
  4. 4. The method of producing a composite solid electrolyte according to claim 1, wherein in the step (2), the viscosity of the hybridization paste is 120 to 150mPa.s.
  5. 5. The method of producing a composite solid electrolyte according to claim 1, wherein in the step (4), the thickness of the composite solid electrolyte is 50 to 200. Mu.m.

Description

Preparation method of composite solid electrolyte Technical Field The invention relates to the technology of the electrolyte field, in particular to a preparation method of a composite solid electrolyte. Background The Li 3InCl6 halide solid electrolyte has become a key candidate material for breaking through the safety bottleneck of a liquid battery by virtue of the room temperature ionic conductivity of 0.1-10mS/cm and the electrochemical stability of the lithium halide solid electrolyte to a high-voltage positive electrode of more than 4.5V. However, the prior Li 3InCl6 -based electrolyte still faces two bottleneck problems In practical application, namely, the structural stability is insufficient, 5-10 mu m gaps are easy to generate among pure halide electrolyte particles, penetrating microcracks are easy to generate under the action of +/-200 MPa stress In charge and discharge cycles, ion transmission channels are broken, the interface problem is outstanding, the chemical activity between Li 3InCl6 and a metal negative electrode is high, particularly, li and Na are easy to generate side reactions of Li 3InCl6 +Li- & gtLiCl+In, high-impedance byproducts are generated, meanwhile, poor contact between a rigid electrolyte and a flexible electrode is further increased, and the interface impedance is further increased to thousands of ohms. In order to solve the problems, researchers respectively propose two technical ideas of porous framework loading and inorganic-organic hybridization. The porous skeleton can raise the compactness and mechanical strength of electrolyte, but the interface side reaction with negative electrode can not be solved when the pure halide is loaded on single skeleton, and the inorganic-organic hybridization can regulate interface property by means of organic phase to inhibit side reaction, but the introduction of organic phase can easily reduce the whole compactness and ionic conductivity of electrolyte, and the mechanical toughness is insufficient when no skeleton is supported, so that the structure collapse easily occurs in circulation. When the two technical ideas are independently applied, the performance short plates exist, and the cooperative optimization of 'structural stability-interface compatibility-high conductivity' cannot be simultaneously realized, so that the industrialization process of the halide solid-state battery is restricted. Therefore, a new solution is needed to solve the above-mentioned problems. Disclosure of Invention In view of the above, the present invention aims at overcoming the drawbacks of the prior art, and its main objective is to provide a method for preparing a composite solid electrolyte, which can effectively solve the problem that the existing Li 3InCl6 halide solid electrolyte cannot achieve stable structure, interface compatibility and high conductivity at the same time after modification. In order to achieve the above purpose, the present invention adopts the following technical scheme: a preparation method of a composite solid electrolyte is characterized by comprising the following steps: (1) The porous gamma-Al 2O3 skeleton pretreatment, namely placing the gamma-Al 2O3 porous skeleton into absolute ethyl alcohol for ultrasonic cleaning for 30 minutes, then taking out and transferring the porous skeleton to a vacuum drying oven, vacuum drying the porous skeleton for 2 hours at 120 ℃, cooling the porous skeleton to room temperature, immersing the porous skeleton into an alcohol solution of APTES, wherein the concentration of the APTES is 5wt%, and the porous skeleton is subjected to constant temperature modification at 60 ℃ for 1.5-2 hours, so that the surface of the porous skeleton is grafted with amino groups, then washing the porous skeleton with the absolute ethyl alcohol for 3 times, placing the porous skeleton in the vacuum drying oven, and vacuum drying the porous skeleton at 80 ℃ for 1 hour to obtain the modified porous Al 2O3 skeleton; (2) The preparation of the hybridized slurry comprises the steps of placing Li 3InCl6 powder in a glove box, ball-milling Li 3InCl6 powder by adopting a high-energy ball-milling tank at the speed of 400-600r/min for 30min, adding a cross-linking agent into a DMF solution of PBO, wherein the concentration of PBO is 10wt%, the mass of PBO is 5% of that of PBO, stirring uniformly to form an organic matrix solution, mixing the ball-milled Li 3InCl6 with LiTFSI, the mass ratio of the ball-milled Li 3InCl6 to LiTFSI is (6.5-7) 1, adding the organic matrix solution, the mass ratio of the ball-milled Li 3InCl6 to the organic matrix solution is (6.5-7) 20-25, dispersing for 40min in the glove box by ultrasonic, and magnetically stirring for 1h to obtain the hybridized slurry; (3) Impregnating and preforming, namely placing the modified porous Al 2O3 skeleton obtained in the step (1) into a vacuum impregnating device, vacuumizing to-0.095 MPa and keeping for 30min, breaking bubbles in the skeleton pores, the