Solid electrolyte membrane, preparation method and battery

A solid electrolyte membrane and base membrane technology, applied in solid electrolytes, non-aqueous electrolytes, secondary batteries, etc., can solve problems such as reducing the lithium ion transport performance of electrolyte membranes, affecting the creep of PEO chains, and improving battery cycle performance. , The effect of improving oxidation resistance and improving interface impedance

Active Publication Date: 2022-06-03
CHINA AVIATION LITHIUM BATTERY RES INST CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The current protection measures for PEO are: (1) co-polymerizing molecules with strong anti-oxidation properties in PEO, this method will affect the creep of the PEO chain and reduce the lithium ion transport performance of the entire electrolyte membrane; (2) in PEO Adding a barrier coating on the surface of the membrane, due to the performance limitations of the barrier coating, also has a greater negative impact on the electrolyte membrane; (3) Adding a lithium ion conductor coating to the surface of the positive electrode, due to the scale strain of the positive electrode material during charging and discharging , the coating needs to face the stability problem

Method used

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  • Solid electrolyte membrane, preparation method and battery
  • Solid electrolyte membrane, preparation method and battery
  • Solid electrolyte membrane, preparation method and battery

Examples

Experimental program
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Effect test

Embodiment 1

[0033]PEO (MW=400000) was dissolved in DMF / acetonitrile (mass ratio of 1:2) to form a 20wt% glue solution, and then lithium salt (LiTFSI) and lithium ion conductor (LLZTO) were added and stirred evenly, and then coated on the base. Membrane 1 (as figure 1 On the A side of the shown), it was dried into a PEO coating with a thickness of 12 μm, which was used for later use. Among them, PEO:LiTFSI:LLZTO=5:2:3 (mass ratio).

[0034] like figure 2 As shown, the PEO coating of the prepared composite membrane was subjected to electrochemical fluorination treatment. The prepared composite film 8 is partially immersed in the Olah reagent solution 5 through a pair of rollers 7 plated with nickel, and the electrolytic cell 4 is made of polytetrafluoroethylene. Olah's reagent is C 5 H 5 N . HF (polypyridinium hydrofluoric acid salt), wherein the HF content is 70%. The composite film 8 is in close proximity to the nickel anode 6 at the counter-roll portion. A voltage of 5V, a curre...

Embodiment 2

[0037] Except that the electrochemical fluorination treatment is different from that of Example 1, other preparation processes are the same as those of Example 1. The electrochemical fluorination treatment process in this embodiment is as follows: a voltage of 5V is applied in the electrolytic cell, a current of 1A is applied, and the rotating speed is 0.2m / min to obtain the first polyethylene oxide film 2 with an F content of 142ppm.

Embodiment 3

[0039] Except that the electrochemical fluorination treatment is different from that of Example 1, other preparation processes are the same as those of Example 1. The electrochemical fluorination treatment process in this example is as follows: apply a voltage of 5V, a current of 3A in the electrolytic cell, rotate slowly, and the rotational speed is 0.15m / min to obtain a PEO film with a F content of 442ppm.

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Abstract

The invention provides a solid electrolyte membrane, its preparation method and battery containing it. The solid electrolyte membrane includes a base film and a first polyethylene oxide film laminated on one surface of the base film, and only the surface of the first polyethylene oxide film towards the outside includes -C 2 h 4‑x f x O‑structure, where x is an integer from 1‑4. The present invention improves the oxidation resistance of the electrolyte membrane and improves the battery life by performing fluorination treatment on the surface of the PEO membrane on the premise that the overall influence on the lithium ion transmission performance of the membrane is minimal; at the same time, the fluorination layer has a strong The bonding effect can improve the interface impedance of the electrolyte membrane-electrode sheet and improve the cycle performance of the battery.

Description

technical field [0001] The invention belongs to the technical field of chemical power sources, and in particular relates to a solid electrolyte membrane, a preparation method thereof and a battery comprising the solid electrolyte membrane. Background technique [0002] Polyethylene oxide (PEO) is widely used as a solid-state electrolyte membrane for lithium-ion batteries due to its optimal lithium-ion transport properties. However, the PEO film will be oxidized and decomposed when it is in contact with the cathode material with a potential to lithium higher than 3.8V. The current protective measures for PEO include: (1) copolymerization of molecules with strong antioxidant properties in PEO, this method will affect the creep of the PEO chain and reduce the lithium ion transport performance of the entire electrolyte membrane; (2) in PEO Adding a barrier coating on the membrane surface also has a great negative impact on the electrolyte membrane due to the performance limitat...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M10/0565H01M10/0525
CPCH01M10/0565H01M10/0525H01M2300/0082Y02E60/10
Inventor 王康平曹晨李旭徐鹏飞华松袁文森蒋嘉琳郑东东
Owner CHINA AVIATION LITHIUM BATTERY RES INST CO LTD
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