Composite electrolyte membrane, lithium metal battery and preparation method of composite electrolyte membrane

Abstract

The invention belongs to the technical field of battery manufacturing, and discloses a composite electrolyte membrane, a lithium metal battery and a preparation method of the composite electrolyte membrane. The composite electrolyte membrane comprises a middle layer which is a solid electrolyte or a diaphragm. A first dressing layer is arranged on the side, used for being connected with a positive plate, of the middle layer and / or a second dressing layer is arranged on the side, used for being connected with a negative plate, of the middle layer, and the first dressing layer is formed by coating first slurry and then drying; and the first dressing layer is formed by coating first slurry, the first slurry comprises first resin containing difluorophosphate radicals, a first polymer binder and a first organic solvent, the second dressing layer is formed by coating and drying second slurry, and the second slurry comprises second resin containing nitrate radicals, a second polymer binder and a second organic solvent. The cycle performance of the lithium metal battery can be effectively improved.

Description

technical field [0001] The invention relates to the technical field of battery manufacturing, in particular to a composite electrolyte membrane, a lithium metal battery and a preparation method for the composite electrolyte membrane. Background technique [0002] Lithium metal battery is a rechargeable battery with lithium metal as the negative electrode. Its energy density is much higher than that of conventional lithium ion batteries with graphite or silicon carbon as the negative electrode, and it has extremely high development potential. However, due to the presence of lithium metal, lithium metal dendrites will be generated on the surface of the negative electrode during the cycle charge and discharge process of lithium metal batteries, which may cause short circuit of lithium metal batteries and greatly reduce the cycle performance of lithium metal batteries. [0003] Lithium nitrate (LiNO 3 ) as an excellent electrolyte additive, although it can form a lithium nitrid...

AI Technical Summary

Problems solved by technology

However, due to the presence of lithium metal, lithium metal batteries will generate lithium dendrites on the surface of their negative electrodes during the cycle charge-discharge process, which may cause a short circuit of the lithium metal battery and greatly reduce the cycle performance of the lithium metal battery.

[0003] Lithium nitrate (LiNO 3 ) as an excellent electrolyte additive, although it can form a lithium nitride protective layer through reduction and decomposition on the negative electrode surface of lithium metal batteries, which can effectively inhibit the growth of lithium dendrites and improve the cycle performance of lithium metal batteries, but because of its The solubility in conventional carbonate electrolytes is poor, which greatly limits its application range

[0004] Similarly, lithium difluorophosphate (LiPO 2 f 2 ) as a positive electrode film-forming additive, although it can form a protective layer by oxidation and decomposition on the surface of the positive electrode of lithium metal batteries, which can effectively inhibit the growth of lithium dendrites and improve the cycle performance of lithium metal batteries, but due to its presence in conventional carbonate electrolysis Poor solubility in liquid, which greatly limits its scope of application

[0005] Although lithium nitrate and lithium difluorophosphate have good solubility in ether solvents, the use of ether solvents will greatly reduce the high-voltage resistance of the electrolyte and limit its compatibility with high-voltage cathode materials

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