CN113823878B

CN113823878B - Preparation method of lithium battery diaphragm with ion transmission regulation and control function

Info

Publication number: CN113823878B
Application number: CN202110792918.4A
Authority: CN
Inventors: 张倩倩; 吴月; 郝振东; 刘晶冰; 金玉红; 汪浩
Original assignee: Beijing University of Technology
Current assignee: Beijing University of Technology
Priority date: 2021-07-13
Filing date: 2021-07-13
Publication date: 2023-07-14
Anticipated expiration: 2041-07-13
Also published as: CN113823878A

Abstract

A preparation method of a lithium battery diaphragm with an ion transmission regulation function belongs to the technical field of lithium batteries. The anode aluminum oxide diaphragm is modified by electronegative polyacrylic acid, and ion transmission is regulated and controlled by utilizing electrostatic repulsion effect, so that the ion selective migration not only increases the carrier migration number for effective electrochemical energy storage and conversion, but also solves the problem caused by anion migration. Can inhibit the nucleation and growth of lithium dendrite after being applied to the lithium battery, and obtain the lithium battery with higher safety and better electrochemical performance.

Description

Preparation method of lithium battery diaphragm with ion transmission regulation and control function

Technical Field

The invention relates to a preparation method of a lithium battery diaphragm with an ion transmission regulation function, and belongs to the technical field of lithium batteries.

Background

The metallic lithium has the highest theoretical specific capacity (3860 mAh g ^-1 ) And the lowest redox potential (-3.04V vs. standard hydrogen electrode) are considered ideal negative electrode materials for the next generation of evolving lithium metal batteries. However, lithium dendrites can be formed in the repeated electroplating/stripping process of the battery, and the lithium dendrites continue to grow to pierce through the diaphragm, so that potential safety hazards such as internal short circuit of the battery are caused, and the development of the lithium battery is restrained.

In conventional liquid electrolytes, anion diffusion can reduce lithium ion transport efficiency, inefficient Li ⁺ Transport can lead to concentration polarization and lithium dendrite growth. Through reasonable modification, the membrane can have the function of regulating ion transmission. Considering the competition relationship between lithium ions and anions in the electrolyte in the transportation, the high t _Li ⁺ The lithium ion selective membrane of (2) is likely to be a powerful tool for fundamentally inhibiting lithium dendrite nucleation.

Thus, polyacrylic acid ([ Poly (acrylic acid) ] was proposed]PAA) modified anodic aluminum oxide diaphragm (anodic aluminum oxide, AAO) to prepare the lithium battery diaphragm with ion transmission regulation and control function. AAO has a uniformly controllable pore size, which is verticalThe pore structure can promote ion transport and charge movement and inhibit lithium dendrite growth. Carboxylic acid radical COO of PAA itself ^- Negatively charged, and utilizes electrostatic repulsion effect to realize selective permeation of lithium ions and promote t _Li ⁺ Inhibit nucleation of lithium dendrite, and make lithium battery better developed in clean energy storage field.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a preparation method of a lithium battery diaphragm with an ion transmission regulation function. The invention is realized by the following technical scheme:

the preparation method of the lithium battery diaphragm with the ion transmission regulation function is characterized by comprising the following steps of:

the AAO diaphragm is clamped between the double-liquid diffusion tanks, a certain amount of PAA solution is taken to be injected into one end of the double-liquid diffusion tank, deionized water is taken to be injected into the other end of the double-liquid diffusion tank, so that one side of the AAO diaphragm is PAA solution, the other side of the AAO diaphragm is deionized water, the PAA on one side penetrates into the water on the other side through the AAO diaphragm by utilizing the concentration difference between the PAA solution and the deionized water, the diaphragm is modified to be negatively charged, the diaphragm is kept stand for 24 hours, the modified diaphragm PAA@AAO is taken out, and the diaphragm with the ion transmission regulation and control function can be obtained after drying.

The PAA solution is prepared by dissolving PAA powder with a polymerization degree of 2000 in deionized water until the PAA powder is completely dissolved, and preferably 20ml of deionized water is used for each 0.1-1g of PAA powder.

The aperture of the AAO diaphragm is 40-70nm.

Compared with the prior art, the invention has the following advantages:

1. the uniform deposition of lithium is promoted by utilizing the uniform and rich vertical nano pore canal structure of AAO;

2. the negative property of PAA is used for limiting the transmission of anions, so that the ion transmission regulation and control function is realized.

Paa@aao separator achieves a full-scale inhibition of lithium dendrites.

Drawings

FIG. 1 is a graph showing the ion mobility versus the PP separator and the PAA@AAO separator tested in example 1 of the invention.

Fig. 2 is a long cycle comparative test chart of a lithium symmetric battery of the PP separator and paa@aao separator obtained by the test of example 1 of the present invention.

FIG. 3 is a schematic illustration of the preparation process.

Detailed Description

The invention will be further elucidated with reference to the drawings and the detailed description, but the invention is not limited to the following examples.

In the following examples, 1mol/L LiPF was used for the electrolyte ₆ /(ec+dmc+emc) (volume ratio 1:1:1); the battery assembly was completed using the glovebox eteux LAB2000 from itex inert gas systems limited; testing the ion migration number by using a Prlington VersasTAT 4 electrochemical workstation; a battery charge-discharge tester CT3008W of Shenzhen Xinwei electronic Co Ltd was used for testing the long cycle.

Example 1

1. 0.9g of PAA powder (polymerization degree 2000) was weighed and dissolved in 20ml of deionized water, and the mixed solution was put into a beaker equipped with a magnet and stirred for 10 minutes until the PAA was completely dissolved. An AAO diaphragm with the diameter of 19mm (aperture of 40-70 nm) is placed in the middle of an H-shaped double-liquid diffusion tank, a proper amount of PAA solution is sucked out by a dropper, one end of the H-shaped double-liquid diffusion tank is injected to the level of the liquid surface and the end face, the other end of the H-shaped double-liquid diffusion tank is injected with deionized water to the level of the liquid surface and the end face, and the H-shaped double-liquid diffusion tank is stood for 24 hours. Taking out the diaphragm PAA@AAO subjected to PAA negative electricity modification, sucking away excessive water by using dust-free paper, and placing the diaphragm PAA@AAO on a culture dish and drying the diaphragm PAA@AAO in a drying box at 100 ℃ for 5 hours.

2. The battery is assembled in a glove box in the sequence of an anode shell, a lithium sheet, electrolyte, a diaphragm, electrolyte, the lithium sheet, a gasket, a spring piece and a cathode shell from bottom to top, the battery is assembled in the glove box filled with argon, the battery is pressurized and sealed by a tablet press, and the battery to be tested can be obtained after standing for 24 hours, wherein the diaphragm adopts a polypropylene diaphragm (PP) and a PAA@AAO diaphragm respectively.

Example 2

The difference between this example and example one is that in step 1, 0.9g of PAA powder (polymerization degree 2000) was weighed and dissolved in 20ml of deionized water, and stirred for 10 minutes until the powder was dissolved to obtain PAA solution. And (3) clamping an AAO diaphragm (with the aperture of 80-100 nm) in the middle of the double-liquid diffusion tank, respectively injecting PAA solution and ion water into two ends of the double-liquid diffusion tank, standing for 24 hours to ensure full permeation, taking out, removing surface water by using dust-free paper, and placing in a culture dish to be dried in a drying oven at the temperature of 100 ℃ for 5 hours to obtain the PAA@AAO diaphragm.

Claims

1. The preparation method of the lithium battery diaphragm with the ion transmission regulation function is characterized by comprising the following steps of:

clamping an anodic aluminum oxide diaphragm in the middle of a double-liquid diffusion pool, taking a certain amount of polyacrylic acid solution to be injected into one end of the double-liquid diffusion pool, taking deionized water to be injected into the other end of the double-liquid diffusion pool, enabling one side of the anodic aluminum oxide diaphragm to be polyacrylic acid solution, the other side of the anodic aluminum oxide diaphragm to be deionized water, enabling polyacrylic acid on one side to penetrate into water on the other side of the anodic aluminum oxide diaphragm through the anodic aluminum oxide diaphragm by utilizing concentration difference between the polyacrylic acid solution and the deionized water, enabling the diaphragm to be modified to be negatively charged, standing for 24 hours, taking out the modified diaphragm polyacrylic acid@anodic aluminum oxide, and drying to obtain the diaphragm with the ion transmission regulation and control function;

the polyacrylic acid solution is prepared by dissolving polyacrylic acid powder with the polymerization degree of 2000 in deionized water until the polyacrylic acid powder is completely dissolved;

the aperture of the anodic aluminum oxide diaphragm is 40-70nm.

2. The method for preparing a lithium battery separator with ion transmission regulation and control function according to claim 1, wherein the polyacrylic acid solution is 20ml of deionized water for every 0.1-1g of polyacrylic acid powder.

3. A lithium battery separator with ion transmission regulating function prepared by the method according to any one of claims 1 to 2.