Sulfur-based cathode composite material and preparation method thereof

A composite material and positive electrode technology, which is applied in the field of sulfur-based positive electrode composite materials and its preparation, can solve the problems that the sulfur content is difficult to meet the industrialization requirements, affect the industrialization process of lithium-sulfur batteries, and easily cause lithium dendrites, etc., so as to suppress the shuttle effect and improve Electrochemical properties, anti-aggregation effect

Active Publication Date: 2016-09-21
SOUNDON NEW ENERGY TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, it also has some defects, such as elemental sulfur is an insulator at room temperature (conductivity at room temperature is 5×10 -30 S / cm); the content of sulfur in the elemental sulfur positive electrode material is difficult to meet the requirements of industrialization; the battery will generate polysulfide lithium during charging and discharging, and polysulfide lithium can be dissolved in the electrolyte and aggregated to the negative electrode and the negative electrode through the electrolyte. The reaction of lithium metal causes a "shuttle effect"; using metal lithium as the negative electrode is likely to cause a series of problems such as lithium crystal dendrites, which all affect the industrialization process of lithium-sulfur batteries

Method used

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  • Sulfur-based cathode composite material and preparation method thereof
  • Sulfur-based cathode composite material and preparation method thereof
  • Sulfur-based cathode composite material and preparation method thereof

Examples

Experimental program
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Embodiment 1

[0029]Preparation of PAN / MCM-41 composite material: select the particle size range of small-pore molecular sieve MCM-41 to be 10nm-100nm, which is beneficial to control the particle size of elemental sulfur in the nanometer range during the subsequent synthesis of elemental sulfur , to prevent the accumulation of elemental sulfur. Weigh MCM-41 and aniline according to the mass ratio of 12:1 (weigh 2g of MCM-41) and place it on an ultrasonic disperser for 2 hours, then let it stand for 6 hours, add 5ml of 1.4mol / L hydrochloric acid solution and place it under nitrogen Under the atmosphere, exhaust the tail gas into the aqueous solution of sodium hydroxide, stir mechanically for 2h, add 2ml of 0.8mol / L ammonium persulfate dropwise, transfer to the water bath and heat to 16°C, continue stirring for 20h, turn off the stirring, and let stand for 2h Finally, the conductive polymer PAN / MCM-41 composite material mixed solution was obtained.

[0030] Preparation of S-PAN / MCM-41 sulfur...

Embodiment 2

[0033] Preparation of PPy / MCM-41 composite material: select mesoporous molecular sieve MCM-41 with a particle size range of 10nm-100nm, disperse 2g molecular sieve MCM-41 in an aqueous solution dissolved with 5g sodium lignin, inject 0.17g new After steaming pyrrole, place it on an ultrasonic disperser for 2 hours, then let it stand for 6 hours, add 2 mL of ferric chloride solution with a concentration of 0.5 mol / L and place it under a nitrogen atmosphere, discharge the tail gas into an aqueous solution of sodium hydroxide, and place it in an ice-water bath Turn on mechanical stirring for 20 hours, turn off the stirring, and stand still for 2 hours to obtain a mixed solution of conductive polymer PPy / MCM-41 composite material supported by molecular sieves.

[0034] The preparation method of the S-PPy / MCM-41 sulfur-loaded composite material is the same as the preparation method of the sulfur-loaded composite material S-PAN / MCM-41 in Example 1 above.

[0035] (S-PPy / MCM-41) Prep...

Embodiment 3

[0037] (S-PAN / MCM-41)TiO 2 Preparation of sulfur-based composite material: According to the synthetic sulfur-loaded material S-PAN / MCM-41 in Example 1, after filtering and drying, weigh the sulfur-loaded material S-PAN / MCM-41:TiO 2 The mass ratio of 6:1 was added to the ball mill, under an inert atmosphere, the rotating speed of the ball mill was 1000 rpm, the ball milling time was 4 hours, and then the obtained product was dried at 5C for 6h, cooled and sieved to obtain a titanium dioxide package. Coated sulfur-based cathode material (S-PAN / MCM-41) TiO 2 .

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Abstract

The invention discloses a sulfur-based cathode composite material and a preparation method thereof. The sulfur-based cathode composite material is represented as (S-R1/MCM-41)R2, in which MCM-41 is a molecular sieve and is a cathode material base body; S is elemental sulfur and is an active constituent; R1 is a conducting polymer, is formed through a synthetic reaction of monomers thereof inside pore channels of the molecular sieve, and serves as a conducting agent and a sulfur-fixing agent; and R2 is a conducting substance, and is coated on the surface of composite material S-R1/MCM-41. The obtained cathode material is charged and discharged under 400 mA.g<-1>, and the first specific discharge capacity is 1390.5 mAh.g<-1> at most; by taking polyaniline as the conducting agent inside the molecular sieve and polypyrrole as the conducting substance, the sulfur-based cathode composite material synthetized by coating outside the material has higher circulation stability performance, the first specific discharge capacity of an assembled battery is 1191.9 mAh.g<-1>, and the capacity retention ratio after 200 times of circulation is 52.17%.

Description

technical field [0001] The invention belongs to the field of new energy materials, and in particular relates to a sulfur-based cathode composite material based on molecular sieve MCM-41, sulfur and a conductive polymer and a preparation method thereof. Background technique [0002] Lithium-ion battery, as a recyclable new energy storage device, has received great attention since it was commercialized. With the increasingly serious environmental problems and energy problems, lithium-ion batteries have become an important technical approach with the most potential to alleviate the energy crisis and control environmental pollution. Compared with other types of secondary batteries, lithium-ion batteries have high output voltage and energy It has been widely studied due to its advantages of high density, low self-discharge rate, long service life, and low environmental pollution, and its uses are becoming more and more extensive. [0003] The cathode materials used in traditiona...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M10/0525
CPCH01M4/362H01M4/38H01M4/624H01M10/0525Y02E60/10
Inventor 冯泽唐泽勋商士波常敬杭刘洪金
Owner SOUNDON NEW ENERGY TECH CO LTD
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