Preparation method and application of nanometer LiF/Fe/graphite positive electrode lithium supplementing slurry

Abstract

The invention discloses a preparation method and an application of nanometer LiF / Fe / graphite positive electrode lithium supplementing slurry; the method comprises the following steps of 1, performingmixing and uniform stirring on LiF, Fe powder and graphite; and step 2, enabling the uniformly mixed LiF, Fe powder and graphite to be added into absolute ethyl alcohol and then transferring the mixture into a high-energy ball milling tank, and carrying out high-energy ball milling under the protection of inert gas to obtain the nanometer LiF / Fe / graphite positive electrode lithium supplementing slurry. By adoption of the method, the obtained nanometer LiF / Fe / graphite positive electrode lithium supplementing slurry can be applied to a lithium ion battery positive electrode for lithium supplementing. After the lithium ion battery is charged to 4.5V for the first time, LiF reacts with Fe to generate FeF3, and Li+ is released; and when the lithium ion battery is discharged to 3.0V, FeF3 does not return to LiF and Fe, and the redundant Li+ is used for compensating Li+ consumption caused by formation of an SEI membrane and lithium loss in subsequent circulation. The preparation method disclosed by the invention is low in raw material cost and simple in preparation process, and the preparation process is clean and environment-friendly.

Description

technical field [0001] The invention belongs to the technical field of energy materials, and relates to a preparation method and application of a LiF / Fe positive electrode lithium supplement slurry, in particular to a preparation method and application of a nano LiF / Fe / graphite positive electrode lithium supplement slurry. Background technique [0002] At present, in the first charging and discharging process of lithium-ion batteries using graphite or silicon carbon as the negative electrode, about 10% of the active lithium in the positive electrode will be consumed, and an irreversible and stable SEI film will be formed on the surface of the negative electrode, resulting in irreversible capacity loss, thereby reducing energy density of lithium-ion batteries. The researchers hope that this part of the irreversible capacity loss can be eliminated by supplementing lithium. Usually, a part of metal lithium powder is supplemented on the surface of the negative electrode, but it...

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Problems solved by technology

[0005] The present invention aims at the problem of low initial coulombic efficiency of existing lithium-ion batteries, and provides a preparation method and application of nano-LiF / Fe / graphite cathode lithium supplement slurry, which contains high specific capacity LiF / Fe and high-conductivity graphite The positive electrode lithium supplement slurry can be obtained by high-energy ball milling, which is simple and easy

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