Method for preparing titanium dioxide and graphene dual-layer co-coated core-shell-structured positive electrode material of lithium-sulfur battery by one-step method

A titanium dioxide, core-shell structure technology, applied in battery electrodes, lithium batteries, nanotechnology for materials and surface science, etc., can solve problems such as complex preparation methods, limited polysulfide shuttle effect, etc., to achieve uniform distribution and good Electrochemical performance, the effect of improving electronic conductivity

Active Publication Date: 2017-06-20
HARBIN INST OF TECH
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Problems solved by technology

[0004] The present invention aims to solve the technical problems of complex preparation methods of graphene-coated sulfur materials in current lithium-sulfur battery cathode materials and the limited shuttl

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  • Method for preparing titanium dioxide and graphene dual-layer co-coated core-shell-structured positive electrode material of lithium-sulfur battery by one-step method
  • Method for preparing titanium dioxide and graphene dual-layer co-coated core-shell-structured positive electrode material of lithium-sulfur battery by one-step method
  • Method for preparing titanium dioxide and graphene dual-layer co-coated core-shell-structured positive electrode material of lithium-sulfur battery by one-step method

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specific Embodiment approach 1

[0032] Specific Embodiment 1: This embodiment is a one-step method for preparing titanium dioxide and graphene double-layer co-coated core-shell structure lithium-sulfur battery positive electrode materials, specifically according to the following steps:

[0033]1. Preparation of graphene oxide paste: add KOH to graphene oxide aqueous solution, heat in a water bath at 95°C for 2 hours, cool to room temperature, centrifuge at 10,000 rpm for 10 minutes, and collect all the paste , and then put all the paste into distilled water for ultrasonic dispersion for 3h to 4h to obtain a graphene oxide paste; the concentration of graphene oxide in the graphene oxide aqueous solution is 1 mg / mL; the graphene oxide aqueous solution The mass ratio of graphene oxide to KOH is 1:8; the concentration of graphene oxide in the graphene oxide paste is 2.5mg / mL~20mg / mL;

[0034] 2. Mix nano-sulfur, nano-titanium dioxide and the graphene oxide paste obtained in step 1 for 7 hours, freeze for 3 hours...

specific Embodiment approach 2

[0035] Specific embodiment two: the difference between this embodiment and specific embodiment one is: the preparation method of the graphene oxide in the graphene oxide aqueous solution described in step one is as follows:

[0036] Add 120mL of concentrated sulfuric acid with a mass fraction of 98% in a 250mL three-necked bottle, then place it in an ice-water bath at 0°C, and then add 5g of graphite and 2.5g of NaNO 3 , magnetically stirred for 30min, then added 3g of powdered KMnO every 10min 4 , added 5 times in total, and continued to react for 2 h under ice-water bath and stirring conditions;

[0037] Then continue stirring for 2h in a constant temperature oil bath at 35°C, slowly add the reactant to 360mL of distilled water, and control the rate of addition so that the reaction temperature does not exceed 90°C, and then continue the constant temperature reaction at 75°C for 1h to obtain brown Suspension, take the excellent suspension and put it in a fume hood, add 1000m...

specific Embodiment approach 3

[0038] Embodiment 3: This embodiment differs from Embodiment 1 in that the concentration of graphene oxide in the graphene oxide paste described in step 1 is 20 mg / mL. Others are the same as in the first embodiment.

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Abstract

The invention discloses a method for preparing a titanium dioxide and graphene dual-layer co-coated core-shell-structured positive electrode material of a lithium-sulfur battery by a one-step method, relates to a preparation method for the positive electrode material of the lithium-sulfur battery, and aims to solve the technical problems of a complex preparation method of a graphene-coated sulfur material and limitation in limiting a shuttle effect of polysulfide of the existing positive electrode material of the lithium-sulfur battery. The preparation method comprises the steps of 1, preparing graphene oxide paste; and 2, performing mixing and ball milling, freezing and reducing, and vacuum drying. According to the method, titanium dioxide is added to an electrode material, so that diffusion and dissolving of polysulfide can be effectively limited through chemical bonds of titanium dioxide and polysulfide; however, the conventional hydrothermal method and chemical vapor deposition method and the like cannot facilitate industrial production of the material; and the hydrophilic nanometer titanium dioxide is adopted by the method, and the material is prepared by the simple process of ball milling, so that possibility is provided for industrial production.

Description

technical field [0001] The invention relates to a preparation method of a cathode material of a lithium-sulfur battery. Background technique [0002] Lithium-sulfur battery cathode sulfur has a theoretical specific capacity of 1675mAh / g and a theoretical energy density of 2567Wh / kg, so it has been widely studied. As one of the most likely next-generation energy storage batteries, sulfur has low cost of ownership, abundant raw materials, and environmental protection Despite these excellent features, the development of lithium-sulfur batteries is hindered by the poor cycle performance and low specific power of sulfur electrodes. The electronic conductivity of sulfur is only 5×10 at room temperature. -30 S / cm, which reduces the utilization of the active material, the volume expansion of 80% during charge and discharge leads to the instability of the electrode structure, and the other is the shuttle effect of polysulfides, which leads to a rapid capacity decay and a lower Coulom...

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Application Information

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IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M10/052B82Y30/00
CPCB82Y30/00H01M4/366H01M4/38H01M4/625H01M4/628H01M10/052Y02E60/10
Inventor 赵力张羽听吴清
Owner HARBIN INST OF TECH
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