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A sepiolite-based lithium-sulfur battery cathode material and its preparation and application method

A technology for lithium-sulfur batteries and positive electrode materials, which is applied in the directions of battery electrodes, lithium batteries, non-aqueous electrolyte battery electrodes, etc., and can solve problems such as low utilization rate, micro-cracks of sulfur electrodes, and poor conductivity of lithium sulfide.

Active Publication Date: 2015-08-12
XIANGTAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Nevertheless, lithium-sulfur batteries still have the following three problems: (1) Lithium polysulfide produced during charging and discharging of lithium-sulfur batteries is easily soluble in organic electrolyte, which gradually reduces the active material of the electrode, and due to the shuttle principle, the dissolved Lithium polysulfide will pass through the separator and reach the lithium sheet of the negative electrode of the battery. The resulting lithium sulfide and other products have poor conductivity and are insoluble, which will cause corrosion of the negative electrode of the battery and increase the internal resistance of the battery, resulting in poor cycle performance of the battery and gradual increase in capacity. attenuation
(2) The conductivity of sulfur is poor, which is not conducive to the high rate performance of the battery. It is impossible to charge and discharge the Li / S battery with 100% sulfur as the positive electrode at room temperature. This is because the ionic conductivity and electronic conductivity of sulfur are very low. It leads to poor electrochemical performance and low utilization rate of sulfur in the electrode. Generally, compounding sulfur with carbon or other conductive materials can solve the problem of poor conductivity.
(3) During the charging and discharging process of sulfur, the expansion and shrinkage of the volume is very large, which may cause battery damage, because during the cycle, the volume deformation of the sulfur electrode in the lithium-sulfur battery is as high as 22%, which may cause microcracks inside the sulfur electrode
The existence of such microcracks and the insulating phase Li 2 The generation of S at the cracks destroys the integrity of the electrode, which eventually aggravates the capacity fading of lithium-sulfur batteries

Method used

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  • A sepiolite-based lithium-sulfur battery cathode material and its preparation and application method

Examples

Experimental program
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Effect test

Embodiment 1

[0027] Pretreatment of sepiolite powder: select sepiolite powder with a particle size of less than 5 μm, wash it with deionized water, then ultrasonically vibrate the washed sepiolite powder for 1 hour, and then dry it in an oven at 85° C. for 24 hours. Add the sepiolite powder to 10mol / L HCl solution for pickling treatment for 2 hours, and then perform pre-activation, keep the sepiolite powder at 200°C for 2 hours under vacuum conditions, remove the water and gas in it, and cool it under vacuum conditions to At room temperature, the purified sepiolite powder material was obtained.

[0028] Mix the pretreated sepiolite powder and elemental sulfur 1:1 evenly, place in a quartz boat, heat to 100°C at 2°C / min under a vacuum of 100Pa, keep the temperature for 2 hours, and then continue to mix the sample Heating to 120°C at a heating rate of 2°C / min, keeping the temperature at a constant temperature for 0.5h, maintaining the vacuum condition and then cooling down to room temperatur...

Embodiment 2

[0030] Select the sepiolite sulfur-carrying material obtained in Example 1 to prepare the nickel-coated sepiolite sulfur-carrying material:

[0031] The sepiolite sulfur-loaded material is pretreated to ensure that the coating metal is evenly coated and has good adhesion.

[0032] 1. Degreasing: Take 5g of sepiolite sulfur-carrying material in 200ml of ethanol solution, add 100ml of 37% HCl, ultrasonically oscillate for 20min at a temperature of 30°C, wash with deionized water until the pH is neutral, and filter to dry.

[0033] 2. Sensitization: the above-mentioned sepiolite sulfur-loaded material was mixed with 10g / L SnCl 2 2H2 Sensitized in O+40g / L HCL solution for 30min, washed with deionized water, and filtered.

[0034] 3. Activation: Put the sensitized sepiolite sulfur-loaded material in 0.5g / L PdCl 2 +0.25mL HCl solution was activated for 30min, washed with deionized water, and filtered to dry.

[0035] 4. Reduction: soak the activated sepiolite sulfur-carrying mate...

Embodiment 3

[0045] The technical process of pretreatment of sepiolite powder is the same as that of Example 1.

[0046] The pretreated sepiolite material and elemental sulfur were uniformly mixed at 1:1, placed in a quartz boat, heated to 155 °C in a tube furnace with Ar gas, and kept at a constant temperature for 12 hours. Continue to heat the mixed sample to 320 °C at a constant temperature. For 6 h, maintain the protective atmosphere conditions and cool to room temperature. The sample was further ground and dried to obtain a sepiolite sulfur-carrying material.

[0047] Preparation of copper-coated sepiolite sulfur-carrying material: It was prepared by the same steps as in Example 2 except that the following solution composition and process were used for reduction and electroless plating.

[0048] Reduction: soak the activated sepiolite sulfur-carrying material in 10% formaldehyde solution for 0.5-2min, wash with deionized water, and filter dry.

[0049] Electroless copper cladding: ...

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Abstract

The invention discloses a lithium sulphur battery positive electrode material based on sepiolite, a preparation method and an application method of the lithium sulphur battery positive electrode material. According to the positive electrode material, the sepiolite is taken as a framework, elemental sulfur is injected into the sepiolite to obtain sulphur-loaded materials which is coated with conducting materials. The sepiolite which is taken as the lithium sulphur battery framework material not only can inhibit the dissolving of polysulfide, but also can structurally control the expansion of the volume of sulphur, and can improve the utilization ratio of sulphur, so that the performance of the lithium sulphur battery can be promoted. The electrical conductivity of the materials is improved by the coating of the conducting materials, and the capacity of the lithium sulphur battery is improved. According to the lithium sulphur battery positive electrode material, the preparation process is simple, the sepiolite belongs to natural environment-friendly materials, the cost is low, and the industrialization of the lithium sulphur battery is facilitated. Meanwhile, due to the introduction of the sepiolite, the industrial transformation and updating of non-metallic minerals can be promoted.

Description

technical field [0001] The invention belongs to the field of new energy materials, and in particular relates to a sepiolite-based lithium-sulfur battery cathode material and a preparation and application method thereof. Background technique [0002] With the increasingly serious environmental pollution and the continuous aggravation of the energy crisis, the development of high energy density, low-cost renewable energy systems has gradually become the focus of people's research. Elemental sulfur is considered to be an excellent cathode material for lithium batteries due to its high specific capacity, low price, environmental friendliness, and light density. Lithium-sulfur batteries use elemental sulfur as the positive electrode reaction material and metal lithium as the negative electrode, and the theoretical energy density can reach 2600Wh / kg. Compared with conventional lithium-ion batteries, lithium-sulfur batteries are able to achieve 3 to 5 times their energy density, a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/38H01M4/66
CPCH01M4/13H01M4/139H01M4/364H01M4/624H01M10/052H01M2004/028Y02E60/10
Inventor 潘勇潘俊安谢淑红伍成马增胜朱经涛李真真
Owner XIANGTAN UNIV