Solid electrolyte membrane, preparation method and battery

A solid electrolyte membrane and battery technology, applied in solid electrolytes, non-aqueous electrolytes, secondary batteries, etc., can solve problems affecting the creep of PEO chains and reduce the lithium ion transmission performance of electrolyte membranes, so as to improve oxidation resistance, Effect of improving battery cycle performance and improving battery life

Active Publication Date: 2021-02-02
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

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Effect test

Embodiment 1

[0033]Dissolve PEO (MW=400000) in DMF / acetonitrile (mass ratio 1:2) to form a 20wt% glue solution, then add lithium salt (LiTFSI) and lithium ion conductor (LLZTO) Membrane 1 (eg figure 1 Shown) on the A side, dried to a PEO coating with a thickness of 12 μm, and set aside. Wherein PEO:LiTFSI:LLZTO=5:2:3 (mass ratio).

[0034] Such as figure 2 As shown, the PEO coating of the prepared composite membrane was subjected to electrochemical fluorination treatment. Pass the prepared composite film 8 through the nickel-plated counter-roller 7, and partially immerse it in the Olah reagent solution 5, and the electrolytic cell 4 is made of polytetrafluoroethylene. Olah's reagent is C 5 h 5 N . HF (pyridinium polyhydrofluoride), wherein the HF content is 70%. The composite film 8 is close to the nickel anode 6 at the part facing the roller. Apply a voltage of 5V and a current of 0.5A in the electrolytic cell 4, and rotate slowly at a speed of 0.2m / min, so that the electrochemic...

Embodiment 2

[0037] Except that the electrochemical fluorination treatment is different from Example 1, other preparation processes are the same as Example 1. The electrochemical fluorination process in this embodiment is as follows: apply a voltage of 5V in the electrolytic cell, a current of 1A, and slowly rotate at a speed of 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 Example 1, other preparation processes are the same as Example 1. The electrochemical fluorination process in this embodiment is as follows: apply a voltage of 5V in the electrolytic cell, a current of 3A, and slowly rotate at a speed of 0.15m / min to obtain a PEO film with an F content of 442ppm.

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Abstract

The invention provides a solid electrolyte membrane, a preparation method thereof and a battery comprising the solid electrolyte membrane. The solid electrolyte membrane comprises a base membrane anda first polyoxyethylene membrane laminated on one surface of the base membrane, only the surface, facing the outer side, of the first polyoxyethylene membrane comprises a -C2H4-xFxO- structure, and xis an integer of 1-4. According to the invention, the surface of a PEO membrane is subjected to fluoridation treatment, so that the oxidation resistance of the electrolyte membrane is improved and theservice life of the battery is prolonged on the premise that the total influence on the lithium ion transmission performance of the membrane is minimum; meanwhile, a fluorinated layer has a relatively strong bonding effect on the surface of a pole piece, so that the interface impedance of the electrolyte membrane and pole piece can be improved, and the cycle performance of the battery is improved.

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 Li-ion batteries due to its optimal Li-ion transport properties. However, the PEO film will be oxidized and decomposed when in contact with the positive electrode material with a lithium potential higher than 3.8V. 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...

Claims

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Application Information

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Patent Type & Authority Applications(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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