PVDF-based composite solid electrolyte and preparation method thereof

A solid electrolyte and electrolyte technology, applied in circuits, electrical components, secondary batteries, etc., can solve the problems of poor interface contact, difficult mass production and processing, low ionic conductivity, etc., to increase ionic conductivity, suitable for Large-scale production, the effect of high ionic conductivity

Pending Publication Date: 2022-03-18
WUHAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The former has high ionic conductivity and mechanical strength, but its inherent rigidity and brittleness make it poor in interface contact with electrodes, and it is difficul

Method used

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  • PVDF-based composite solid electrolyte and preparation method thereof
  • PVDF-based composite solid electrolyte and preparation method thereof
  • PVDF-based composite solid electrolyte and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Accurately weigh 0.239g LiTFSI and 0.0789g SN in the glove box, then dissolve them together in 15mL N,N-dimethylformamide (DMF), stir the resulting mixture at room temperature until completely dissolved, then add 0.4g PVDF and Continue to stir until completely dissolved to obtain a homogeneous and transparent composite solution. Accurately weigh 0.071g Li 6.4 Ga 0.2 La 3 Zr 2 o 12 Powder, which is added to the aforementioned composite solution, ultrasonically dispersed and then stirred for 24 hours to obtain a uniform composite slurry. The composite slurry was poured on a polytetrafluoroethylene plate, and then vacuum-dried at 60°C for 48 hours to remove the solvent, and finally the desired composite solid electrolyte membrane was obtained, denoted as PVDF-LiTFSI-10%LLZO-10%SN.

[0026] In order to further understand the performance of the composite solid electrolyte membrane, it is processed into the required shape, and it is stacked with the positive and negative...

Embodiment 2

[0028] Accurately weigh 0.117g LiFSI and 0.034g SN in the glove box, then dissolve them together in 12mL N-methylpyrrolidone (NMP), stir the resulting mixture at 50°C until completely dissolved, then add 0.4g PVDF and continue stirring until Completely dissolved to obtain a homogeneous and transparent compound solution. Accurately weigh 0.129g of LLZO powder, add it to the aforementioned composite solution, and stir for 12 hours after ultrasonic dispersion to obtain a uniform composite slurry. The composite slurry was poured on a polytetrafluoroethylene plate, and then vacuum-dried at 80°C for 24 hours to remove the solvent, and finally the desired composite solid electrolyte membrane was obtained, denoted as PVDF-LiFSI-20%LLZO-5%SN.

[0029]The composite solid electrolyte membrane is processed into the desired shape, stacked and pressed together with the positive and negative electrodes in the glove box, and finally sealed in a button battery or aluminum-plastic composite pac...

Embodiment 3

[0031] Accurately weigh 0.1g LiBOB and 0.152g SN in the glove box, then dissolve them together in 15mL dimethyl sulfoxide (DMSO), stir the resulting mixture at 60°C until completely dissolved, then add 0.5g PVDF and continue stirring until Completely dissolved to obtain a homogeneous and transparent compound solution. Accurately weigh 0.258g of LLZO powder, add it to the aforementioned composite solution, and stir for 10 hours after ultrasonic dispersion to obtain a uniform composite slurry. The composite slurry was poured on a polytetrafluoroethylene plate, and then vacuum-dried at 70°C for 36 hours to remove the solvent, and finally the desired composite solid electrolyte membrane was obtained, denoted as PVDF-LiBOB-30%LLZO-15%SN.

[0032] The composite solid electrolyte membrane is processed into the desired shape, stacked and pressed together with the positive and negative electrodes in the glove box, and finally sealed in a button battery or aluminum-plastic composite pac...

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Abstract

The invention relates to a PVDF-based composite solid electrolyte and a preparation method thereof, the composite solid electrolyte is composed of a PVDF matrix, a lithium salt, an oxide inorganic solid electrolyte powder and a plastic crystal compound succinonitrile, and the PVDF-based composite solid electrolyte is prepared into a film through a solution casting method or a tape casting method and then assembled into an all-solid-state battery. According to the invention, the succinonitrile, the oxide inorganic solid electrolyte and the PVDF matrix are compounded, on one hand, the crystallinity of the polymer matrix is effectively reduced, and the dissociation degree of lithium salt in the polymer matrix is increased, so that the migration ability of lithium ions is improved, and on the other hand, the succinonitrile is used as a plasticizer, so that the flexibility of the composite solid electrolyte membrane is increased to a certain extent; the interface impedance between the positive electrode and the negative electrode is reduced, and the cycle performance and the rate performance of the all-solid-state battery are improved. Experimental results show that the composite solid electrolyte provided by the invention has relatively high ionic conductivity, relatively wide electrochemical window and good mechanical property and thermal stability, and has a wide application prospect in the field of all-solid-state batteries.

Description

technical field [0001] The invention relates to the technical field of solid electrolyte materials, in particular to a PVDF-based composite solid electrolyte and a preparation method thereof. Background technique [0002] Among all kinds of secondary batteries, lithium-ion batteries are widely used in portable electronic devices, electric vehicles, and energy storage due to their advantages such as light weight, high working voltage, no memory effect, and small self-discharge. However, the organic electrolyte used in lithium-ion batteries is flammable, easy to leak, and has poor chemical stability, making it a more prominent safety problem. Solid electrolyte materials have superior thermal stability and excellent electrochemical performance, and are gradually replacing separators and electrolytes in traditional lithium-ion batteries. Therefore, the development of all-solid-state lithium batteries with higher safety and higher energy density has become a solution to the above...

Claims

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Application Information

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IPC IPC(8): H01M10/0565C08L27/16C08K3/22C08K5/435C08J5/18
CPCH01M10/0565C08J5/18C08J2327/16C08K3/22C08K5/435Y02E60/10
Inventor 陈斐曹诗雨宋尚斌沈强张联盟
Owner WUHAN UNIV OF TECH
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