Lithium-sulfur battery composite positive electrode and preparation method thereof

A composite positive electrode and lithium-sulfur battery technology, applied in the field of electrochemical batteries, can solve the problems of reducing the relative content of active material sulfur, low battery capacity retention rate, increase of binders and conductive agents, etc., to achieve enhanced electronic conductivity, The effect of maintaining structural stability, improving specific capacity and cycle life

Active Publication Date: 2017-09-08
NORTHWESTERN POLYTECHNICAL UNIV
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Problems solved by technology

Keyu Xie et al. [Advanced Materials, 2016, 6, 29-34] limit the dissolution of polysulfides by adding barium titanate particles in the positive electrode material. Although this scheme is simple and feasible, the addition of barium titanate to the positive electrode material requires The increase of binder and conductive agent reduces the relative content of active material sulfur, which reduces the mass specific capacity of the battery, and the capacity retention rate of the battery is not high

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  • Lithium-sulfur battery composite positive electrode and preparation method thereof

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preparation example Construction

[0032] The positive electrode modification and preparation method of the lithium-sulfur battery of the present invention mainly includes the following steps:

[0033] Step 1, preparation of ferroelectric material and graphene mixed spray coating.

[0034] Disperse graphene in NMP so that the concentration of graphene is 1mg / ml-3mg / ml, sonicate for 0.5h, then add ferroelectric material to make the concentration of ferroelectric material 0.5mg / ml-3mg / ml, stir for 0.5 h and ultrasonication for 0.5h to obtain a uniformly dispersed mixed solution; then place the resulting solution in a spray gun in a nitrogen-filled glove box, and then spray the mixed solution on an alcohol-cleaned aluminum foil to keep the thickness of the mixed material at 0.2μm-5μm, finally dry the sprayed aluminum foil in a vacuum oven at 60°C for 12h-24h.

[0035] Step 2, preparation of carbon / sulfur slurry scrape coating:

[0036]Method 1: Weigh 70mg of nano-sulfur, 20mg of conductive carbon black (Super P)...

Embodiment 1

[0041] Graphene is dispersed in NMP, makes the concentration of graphene 1mg / ml, ultrasonic 0.5h, adds the potassium niobate (KNbO 3 ), so that KNbO 3 The concentration is 2mg / ml, stirred for 0.5h and ultrasonicated for 0.5h to obtain a uniformly dispersed mixed solution; then the resulting solution was placed in a spray gun in a glove box filled with nitrogen, and then the mixed solution was sprayed on an alcohol-cleaned aluminum foil Keep the thickness of the mixed material at 2 μm, and finally dry the sprayed aluminum foil in a vacuum oven at 60° C. for 18 hours.

[0042] Weighed 105 mg of nano-sulfur, 30 mg of conductive carbon black (Super P) and 15 mg of polyvinylidene fluoride (PVDF) at a mass ratio of 7:2:1, and ground them in a mortar for 0.5 h. First, PVDF was added to 0.5 mg N-methylpyrrolidone (NMP) solution, and stirred magnetically for 6 h; then, adding ground nano-sulfur particles, stirring for 0.5 h, and ultrasonication for 1 h (ultrasonic power 300 W), and fi...

Embodiment 2

[0046] Graphene is dispersed in NMP, makes the concentration of graphene 2mg / ml, ultrasonic 0.5h, adds the barium titanate (BaTiO 3 ), making BaTiO 3 The concentration is 1mg / ml, stirred for 0.5h and ultrasonicated for 0.5h to obtain a uniformly dispersed mixed solution; then the resulting solution was placed in a spray gun in a glove box filled with nitrogen, and then the mixed solution was sprayed on an alcohol-cleaned aluminum foil Keep the thickness of the mixed material at 1.5 μm, and finally dry the sprayed aluminum foil in a vacuum oven at 60° C. for 20 h.

[0047] Weigh 105mg of nano-sulfur, 30mg of conductive carbon black (Super P), and 15mg of polyvinylidene fluoride (PVDF) at a mass ratio of 7:2:1, mix the weighed materials into a mortar, and grind for 1 hour to obtain a mixed Homogeneous positive electrode material; then, put the mixed material into a hydrothermal kettle in a nitrogen-filled glove box, and transfer the hydrothermal kettle to a tube furnace filled ...

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Abstract

The invention provides a lithium-sulfur battery composite positive electrode and a preparation method thereof. The lithium-sulfur battery composite positive electrode mainly comprises a mixed spraying layer of a ferroelectric material and graphene, a carbon/sulfur paste scrapping layer and a ferroelectric material spraying layer. The volume expansion of the positive electrode material during the charge-discharge process can be reduced by the two spraying layers, and the structural stability is maintained; and a long-chain polysulfide is doubly absorbed by the two spraying layers, the dissolution of the polysulfide is limited, a shuttle flying effect is effectively solved, the specific capacity of the lithium-sulfur battery is improved, and the cycle lifetime of the lithium-sulfur battery is prolonged. By a simple spraying process, a thin film layer with a controllable thickness is sprayed, and the spraying process is suitable for wide production.

Description

technical field [0001] The invention belongs to the field of electrochemical batteries, in particular to a lithium-sulfur battery composite positive electrode and a preparation method thereof. Background technique [0002] With the progress and development of society, battery energy storage systems are playing an increasingly important role. On the one hand, the improvement of people's living standards has made electronic products such as mobile phones and notebooks a necessity for most people. With the rapid development of these electronic products, the requirements for batteries are also getting higher and higher. On the other hand, the energy crisis and environmental pollution problems are becoming more and more prominent, and the development of renewable energy and electric vehicles has become an irresistible trend. In the process of effective utilization of renewable energy such as wind energy, solar energy, and tidal energy, it is urgent to solve the problem of energy...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M4/13H01M4/139H01M10/052
CPCH01M4/13H01M4/139H01M4/366H01M4/38H01M4/62H01M4/625H01M4/628H01M10/052Y02E60/10
Inventor 谢科予沈超游悠张坤魏秉庆
Owner NORTHWESTERN POLYTECHNICAL UNIV
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