A kind of negative pole piece of lithium ion battery and preparation method thereof

A technology for lithium-ion batteries and negative pole pieces, applied in battery electrodes, secondary batteries, circuits, etc., can solve the problems of heavy electrode materials and achieve the effects of small thickness, effective lithium ion exchange, and large number of thin-layer structures

Active Publication Date: 2019-12-17
SHAANXI UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In order to overcome the problem that the quality of existing electrode materials is too heavy, the object of the present invention is to provide a method for preparing negative pole pieces of lithium ion batteries

Method used

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  • A kind of negative pole piece of lithium ion battery and preparation method thereof
  • A kind of negative pole piece of lithium ion battery and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] Take 10g of carboxymethylcellulose aqueous solution with a concentration of 1%, 0.1g of conductive carbon and 0.3g of graphite, and place them in a ball mill for ball milling for 15min. Pour the ground slurry into 10 weighing bottles respectively, and freeze into ice cubes at low temperature. Under the low pressure of 5 Pa, the moisture in the ice cubes is evaporated. The obtained spongy cylinder can be used as a pole piece.

[0018] The lithium sheet is used as the counter electrode and the prepared pole piece is packaged in a 2032 battery case, and the cycle performance test is carried out at a current density of 50mA / g in the battery test system. The test results show that the specific capacity of the pole piece is 300mAh / g , but a 0.5g pole piece can store 150mAh of electricity. And charge and discharge 500 times, the capacity remains unchanged.

[0019] figure 1 For the thin layer structure when no conductive carbon and active material are added in this embodim...

Embodiment 2

[0022] Take 15g of 2% sodium alginate aqueous solution, 0.3g of conductive carbon and 0.4g of silicon powder, and put them in a ball mill for 15min. Pour the ground slurry into 10 weighing bottles respectively, and freeze into ice cubes at low temperature. Under the low pressure of 5 Pa, the moisture in the ice cubes is evaporated. The obtained spongy cylinder can be used as a pole piece.

[0023] The lithium sheet is used as the counter electrode and the prepared pole piece is packaged in a 2032 type battery case, and the cycle performance test is carried out at a current density of 50mA / g in the battery test system. The test results show that the specific capacity of the pole piece is 1200mAh / g , and the specific capacity remains above 800 mAh / g after 100 charge-discharge cycles.

Embodiment 3

[0025] Take 20g of carboxysodium alginate aqueous solution with a concentration of 0.5%, 0.1g of conductive carbon and 0.3g of graphite, and put them in a ball mill for 15min. Pour the ground slurry into 10 weighing bottles respectively, and freeze into ice cubes at low temperature. Under the low pressure of 5 Pa, the moisture in the ice cubes is evaporated. The obtained spongy cylinder can be used as a pole piece.

[0026] The lithium sheet is used as the counter electrode and the prepared pole piece is packaged in a 2032 battery case, and the cycle performance test is carried out at a current density of 50mA / g in the battery test system. The test results show that the specific capacity of the pole piece is 300mAh / g , but a 0.5g pole piece can store 150mAh of electricity. And charge and discharge 500 times, the capacity remains unchanged.

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Abstract

The invention discloses a negative pole piece of a lithium-ion battery. The negative pole piece comprises the following components by mass percentages: 20-30% of a high-molecular polymer, 20-30% of conductive carbon and the balance of negative active material. The invention further discloses a preparation method of the negative pole piece of the lithium-ion battery. The preparation method comprises the following steps of preparing a water solution with the concentration of 0.5-2% from the high-molecular polymer, mixing the water solution with the conductive carbon and the negative active material and carrying out ball-milling until the conductive carbon, the negative active material and the high-molecular polymer are mixed evenly; freezing slurry obtained through ball-milling in the firststep, and carrying out vacuum freeze drying to prepare the pole piece. The negative pole piece gets rid of a weight burden caused by a current collector in a traditional pole piece; the content of effective components of an overall negative electrode is higher; the thin layer structures are large in number and small in thickness; and the effective components in the negative pole piece can be moreeffectively subjected to lithium ion exchange.

Description

technical field [0001] The invention relates to the technical field of electrode materials, in particular to a lithium-ion battery pole piece and a preparation method thereof. Background technique [0002] Lithium-ion batteries are one of the most important methods of storing electrical energy in today's society. The negative electrode is an important part of it. Usually, the preparation method of the lithium-ion battery negative electrode is to grind the electrode sheet materials such as binder, conductive agent and graphite into slurry. Coat the prepared slurry on the surface of copper foil. After the slurry is dried, it can be used after cutting into the desired shape. During this process, the copper foil acts as a current collector and provides an attachment carrier for negative electrode materials such as graphite. The slurry forms a thin layer structure on the surface of the current collector during the drying process. The thickness of the thin layer should not be h...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/36H01M4/583H01M4/62H01M10/0525H01M4/60
CPCH01M4/362H01M4/583H01M4/60H01M4/625H01M10/0525Y02E60/10
Inventor 杨晓武王霞秋列维李培枝师永民
Owner SHAANXI UNIV OF SCI & TECH
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