Composite material for positive pole of lithium-sulfur battery, and positive pole and battery both made of same

A technology of lithium-sulfur batteries and composite materials, which is applied in the direction of battery electrodes, lithium batteries, non-aqueous electrolyte battery electrodes, etc., which can solve the problems of active material loss, deterioration of electrolyte ion conductivity, and damage to the physical structure of electrodes.

Active Publication Date: 2012-08-01
JIANGXI SUKEER NEW MATERIAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Yao Zhendong et al. (Yao Zhendong, Wei Wei, Wang Jiulin, etc. Research progress on positive electrodes of lithium-sulfur secondary batteries. Acta Physicochemical Society, 2011, 27(5): 1005-1016.) pointed out that there are still several key problems in lithium-sulfur secondary batteries: ( 1) Elemental sulfur is an insulator at room temperature; (2) Elemental sulfur will be reduced to easily soluble polysulfides during the discharge process, resulting in the loss of active materials, and polysulfides will deteriorate the electrolyte after being dissolved in the electrolyte. (3) The polysulfide compound dissolved in the electrolyte directly contacts the metal lithium negative electrode, and a self-discharge reaction occurs; (4) The sulfur electrode will shrink and expand accordingly during the charging and discharging process, which will destroy the physical properties of the electrode to a certain extent. structure
Although the carbon nanotube / sulfur composite material has obvious advantages compared with other composite materials, it still has some urgent needs for improvement, such as: the total content of sulfur is not large, the utilization rate of sulfur is not high, the cycle stability needs to be improved

Method used

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  • Composite material for positive pole of lithium-sulfur battery, and positive pole and battery both made of same
  • Composite material for positive pole of lithium-sulfur battery, and positive pole and battery both made of same
  • Composite material for positive pole of lithium-sulfur battery, and positive pole and battery both made of same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0043] This embodiment provides a lithium-sulfur battery, which is prepared by the following steps:

[0044] 1. Synthesis of polynaphthalene:

[0045] Put 4 g of dried 3,4,9,10-diphenyltetracarboxylic anhydride (PTCDA) in a tube electric furnace, and after three times of vacuuming and filling with argon, adjust the argon flow rate (25mL / min), The tail gas absorption device (absorbing liquid is saturated aqueous solution of calcium hydroxide), and then under the condition that the initial temperature is room temperature, the temperature is raised at a rate of 5°C / min, and the temperature is raised to 530°C, kept at this temperature for 8 hours, and then continued to The temperature was raised at a rate of 5°C / min, the temperature was raised to 1000°C, and maintained at this temperature for 6 hours, and then the temperature was naturally lowered to obtain polynaphthalene, whose infrared spectrum was as follows Figure 6 shown.

[0046] 2. Preparation of battery cathode sheet: ...

Embodiment 2

[0052] This embodiment provides a lithium-sulfur battery, which is prepared by the following steps:

[0053] 1, the synthesis of polynaphthalene is with embodiment 1.

[0054] 2. Preparation of battery cathode sheet:

[0055] Mix the synthesized polynaphthalene and sulfur at a mass ratio of 1:4, thoroughly grind them in a mortar, and then put them into a tube electric furnace for calcination (first raise the temperature to 150°C, keep it for 5h-8h, then continue to heat up to 300°C, And keep at this temperature for 2-3h);

[0056] Mix the calcined product in a mortar, then mix it with conductive agent carbon black and PVDF in a mass ratio of 7:2:1, grind, mix well, apply it on aluminum foil, dry it at 60-70°C, and press into a positive plate.

[0057] 3. Battery assembly:

[0058] In the glove box, combine the above-mentioned positive electrode, negative electrode, diaphragm, electrolyte, and shell together to form a button battery, and let it stand for 24 hours to test; w...

Embodiment 3

[0060] This embodiment provides a lithium-sulfur battery, which is prepared by the following steps:

[0061] 1. Synthesis of nitrated compounds of polynaphthalene:

[0062] Put 2g of the polynaphthalene synthesized in Example 1 in a 250mL three-necked bottle, then add 50mL of sulfuric acid (98wt% concentration), stir, heat to 80°C, and dropwise add a concentration of 65-68wt to the there-necked bottle through a constant pressure funnel. % nitric acid (24mL) and concentration are the mixed acid of the sulfuric acid (28mL) of 98wt%, in the process of dripping mixed acid, keep internal temperature at 80 ℃ all the time, drop complete, continue to react at this temperature for 1.5 hours, then Naturally cool to room temperature, then pour the reaction liquid into 300mL ice water, stir well, add an appropriate amount of alkali to neutralize until the pH=7, filter, then wash the filtered solid with high-purity water 3 times, dry Dry, and finally obtain 2.68g product, namely the nitra...

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Abstract

The invention relates to a composite material for a positive pole of a lithium-sulfur battery, and a positive pole and a battery both made of the material. The composite material is the mixture of polynaphthylene or polynaphthylene derivative with the mass percentage of 20-34 percent, and sulfur. The preparation method for the composite material comprises the steps that firstly, the polynaphthylene or the polynaphthylene derivative is uniformly mixed with the sulfur; secondly, the mixture is placed in an electric tube furnace at the temperature of 150 DEG C for 5-8 hours, and then at the temperature of 300 DEG C for 2-3 hours; and lastly, the material is reduced to room temperature through natural cooling, so as to obtain the composite material. The invention also provides the positive pole for the lithium-sulfur battery and the battery which are made of the composite material. The lithium-sulfur battery provide by the invention has high discharge specific capacity, meanwhile, the utilization ratio of active substance is effectively improved, the cycling stability of the battery is also improved to a certain extent, and the cost of the battery is reduced.

Description

technical field [0001] The invention relates to a lithium-sulfur battery positive electrode composite material, a positive electrode and a battery made of the same, and belongs to the technical field of energy materials. Background technique [0002] Judging from the current development of batteries, the production process of lithium-ion batteries (including lithium-sulfur batteries) is becoming more and more mature, and it is gradually applied to all aspects of modern life. In recent years, major breakthroughs have been made in the negative electrode materials of lithium-ion batteries, but the development of positive electrode materials for lithium-ion batteries has been slow. 4 , or LiMn with spinel structure 2 o 4 , the theoretical specific capacity is less than 200mAh·g -1 . Therefore, the development of new cathode materials with high energy density, long cycle life, low cost and environmental friendliness is particularly important. The theoretical energy density o...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/13H01M10/052
CPCY02E60/122Y02E60/10
Inventor 陈飞彪廖维林熊云奎
Owner JIANGXI SUKEER NEW MATERIAL
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