Lithium-sulfur battery diaphragm and preparation method thereof

A lithium-sulfur battery and separator technology, applied in the field of lithium battery and its preparation, can solve problems such as uneven surface of lithium metal negative electrode, reduction of coulombic efficiency of lithium-sulfur battery, loss of sulfur-containing components of the battery, etc., to inhibit the growth of lithium dendrites , Improve cycle efficiency, improve cycle stability and safety

Active Publication Date: 2019-05-14
SHENYANG INSTITUTE OF CHEMICAL TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Compared with traditional lithium-ion batteries, the intrinsic characteristics of the multi-electron reaction of sulfur molecules form the characteristics of high-capacity electrode materials, but at the same time lead to more complex lithium-sulfur battery systems, mainly the following problems: (1) Safety issues
The surface of the metal lithium negative electrode is uneven and uneven, causing lithium ions to accumulate on the surface of the negative electrode to form dendrites, which will pierce the separator and cause a short circuit between the positive and negative electrodes of the battery, resulting in combustion and explosion of the battery; (2) sulfide dissolution problem
Sulfur electrodes produce soluble polysulfides during charging and discharging. On the one hand, high-order polysulfides diffuse across the diaphragm and directly react with metal lithium anodes to form low-order polysulfides, which leads to side reaction cycles in lithium-sulfur batteries. That is, the shuttle effect, which reduces the Coulombic efficiency of lithium-sulfur batteries; on the other hand, it also leads to the loss of sulfur-containing components in the battery, which makes the battery performance rapidly decay

Method used

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  • Lithium-sulfur battery diaphragm and preparation method thereof
  • Lithium-sulfur battery diaphragm and preparation method thereof
  • Lithium-sulfur battery diaphragm and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Step 1: Soak 20g of K-type carrageenan powder in 50g of NaOH solution with a concentration of 3mol / L, and magnetically stir (250rpm) in a water bath at 50°C for 30 minutes to obtain a clear and transparent solution. Centrifuge at 3500 rpm for 5 minutes, take the supernatant and add absolute ethanol to adjust the concentration to 10%, to prepare an electrospinning solution.

[0022] Step 2: Put the electrospinning solution obtained in step 1 into the spinneret, wind the 5 μm polyethylene diaphragm on the receiving drum, the speed of the receiving drum is 400rpm, and the distance from the spinneret to the receiver drum is 12cm. The power output was 15kV static voltage, the temperature was 30°C, the humidity was 20% and the spinning speed was 0.002mm / s, and the polyethylene separator coated with carrageenan gel coating on one side was prepared.

[0023] Step 3: the polyethylene diaphragm that the single side that step 2 obtains is coated with carrageenan gel coating is wou...

Embodiment 2

[0025] Step 1: Soak 30g of L-type carrageenan powder in 200g of NaOH solution with a concentration of 5mol / L, and magnetically stir (280rpm) in a water bath at 60°C for 40 minutes to obtain a clear and transparent solution. Centrifuge at 3500 rpm for 5 minutes, take the supernatant and add absolute ethanol to adjust the concentration to 11%, to prepare an electrospinning solution.

[0026] Step 2: Put the electrospinning solution obtained in step 1 into the spinneret, wind the 15 μm polyvinylidene fluoride diaphragm on the receiving drum, the speed of the receiving drum is 500 rpm, and the distance from the spinneret to the receiver drum is 15 cm. The high-voltage DC power supply output 18kV static voltage, the temperature is 35 ℃, the humidity is 22% of the environment, the spinning speed is 0.003mm / s, and the polyvinylidene fluoride diaphragm coated with carrageenan gel coating on one side is prepared. .

[0027] Step 3: Wind the polyvinylidene fluoride diaphragm coated wit...

Embodiment 3

[0029] Step 1: Soak 20g of K-type carrageenan powder and 20g of I-type carrageenan powder in 300g of NaOH solution with a concentration of 6mol / L, and stir magnetically (320rpm) in a water bath at 70°C for 50 minutes to obtain clarification transparent solution, centrifuge the obtained solution at 3500 rpm for 5 minutes, take the supernatant and add absolute ethanol to adjust the concentration to 12%, to prepare an electrospinning solution.

[0030] Step 2: Put the electrospinning solution obtained in step 1 into the spinneret, wind the 20 μm non-woven fabric diaphragm on the receiving drum, the speed of the receiving drum is 600 rpm, and the distance from the spinneret to the receiver drum is 18 cm. The output of the DC power supply is 20kV static voltage, the temperature is 40°C, the humidity is 25% and the spinning speed is 0.005mm / s, and the non-woven separator coated with carrageenan gel coating on one side is prepared.

[0031] Step 3: Wind the non-woven membrane of the ...

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Abstract

The invention provides a lithium-sulfur battery diaphragm and a preparation method thereof. Carrageenan gel and a conventional diaphragm are compounded through an electrostatic spinning method to prepare the novel lithium-sulfur battery diaphragm, and the lithium-sulfur battery diaphragm has the advantages of being good in electrolyte wettability, resistant to high temperature, anti-flame and capable of effectively inhibiting the shuttle effect and growth of lithium dendrites, and the circulating stability and safety of a lithium-sulfur battery are improved; and meanwhile, the lithium-sulfur battery compound diaphragm has the excellent heat stability, can resist to high temperature, and can keep the normal work state in the high-temperature environment, the working temperature of the battery can be further increased substantially, and the safety of the battery can be further improved substantially. According to the method, the raw material cost is low, the technology is simple, and mass production is easy.

Description

technical field [0001] The invention relates to a lithium battery and a preparation method thereof, in particular to a lithium-sulfur battery diaphragm and a preparation method thereof. Background technique [0002] Lithium-sulfur batteries have high energy density and can be used in the fields of individual power supplies, drones and passenger vehicles. Lithium-sulfur batteries use metallic lithium as the negative electrode, which poses a safety hazard when used. Due to the inhomogeneity of the lithium metal surface, lithium dendrites are easily generated during the cycle, causing a short circuit inside the battery and causing a fire to burn. The energy density of lithium-sulfur batteries is about 3-5 times that of ordinary batteries. During the charging and discharging process, the heat is severe. The overheating of the battery itself can easily lead to thermal runaway of the battery, causing fire or even explosion. The use of functional separators can inhibit the occurr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/16H01M2/14D01D5/00D04H1/4326D04H1/728H01M50/403H01M50/44
CPCY02E60/10
Inventor 王娜滕海伟张静王昱淼徐爽付彭
Owner SHENYANG INSTITUTE OF CHEMICAL TECHNOLOGY
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