Cathode material for high-capacity graphene lithium sulphur battery and preparation method of cathode material

A positive electrode material, lithium-sulfur battery technology, applied in the field of electrochemical applications, can solve the problems of reducing ohmic resistance, poor adhesion between slurry and current collector, etc., to reduce ohmic resistance and solve poor adhesion , the effect of increasing conductivity

Inactive Publication Date: 2015-07-01
SHANDONG YUHUANG NEW ENERGY TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to propose a high-capacity graphene lithium-sulfur battery positive electrode material and its preparation method to solve the problem of poor adhesion between the slurry and the current co

Method used

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  • Cathode material for high-capacity graphene lithium sulphur battery and preparation method of cathode material
  • Cathode material for high-capacity graphene lithium sulphur battery and preparation method of cathode material
  • Cathode material for high-capacity graphene lithium sulphur battery and preparation method of cathode material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] One coat:

[0021] (1) Add 0.1g of PVDF (polyvinylidene fluoride) to 1.15g of NMP (N-methylpyrrolidone), keep the temperature at 40°C, and magnetically stir for 4 hours to form a PVDF solution.

[0022] (2) Add 0.9g graphene to 4.5g NMP, stir magnetically for 6 hours, put it into an ultrasonic oscillator with an ultrasonic power of about 100 W, and oscillate ultrasonically for 1 hour, then add 1.25g PVDF solution and an appropriate amount of NMP to adjust the slurry Viscosity, continued magnetic stirring for 2 hours, coated the prepared slurry on aluminum foil by casting method, and dried it in a vacuum oven at 120°C for 2 hours to obtain a graphene-coated aluminum foil current collector. The number of graphene sheets used is 4-7 layers, with good crystallinity and a specific surface area of ​​about 380 m 2 / g, the electrical conductivity is about 3520 S / m, and the thickness of the graphene coating is 4 μm.

[0023] Secondary coating:

[0024] (1) Mix graphene an...

Embodiment 2

[0029] One coat:

[0030] (1) Add 0.1g of PVDF to 1.15g of NMP, keep the temperature at 40°C, and magnetically stir for 4h to form a PVDF solution.

[0031] (2) Add 0.9g graphene to 4.5g NMP, stir magnetically for 6 hours, put it into an ultrasonic oscillator with an ultrasonic power of about 100 W, and oscillate ultrasonically for 1 hour, then add 1.25g PVDF solution and an appropriate amount of NMP to adjust the slurry Viscosity, continued magnetic stirring for 2 hours, coated the prepared slurry on aluminum foil by casting method, and dried it in a vacuum oven at 120°C for 2 hours to obtain a graphene-coated aluminum foil current collector. The number of graphene sheets used is 4-7 layers, with good crystallinity and a specific surface area of ​​about 380 m 2 / g, the electrical conductivity is about 3520 S / m, and the thickness of the graphene coating is 4 μm.

[0032] Secondary coating:

[0033](1) Mix graphene and sublimed sulfur evenly in a mixer at a mass ratio of 1...

Embodiment 3

[0038] One coat:

[0039] (1) Add 0.1g of PVDF (polyvinylidene fluoride) to 1.15g of NMP (N-methylpyrrolidone), keep the temperature at 40°C, and magnetically stir for 4 hours to form a PVDF solution.

[0040] (2) Add 0.9g graphene to 4.5g NMP, stir magnetically for 6 hours, put it into an ultrasonic oscillator with an ultrasonic power of about 100 W, and oscillate ultrasonically for 1 hour, then add 1.25g PVDF solution and an appropriate amount of NMP to adjust the slurry Viscosity, continued magnetic stirring for 2 hours, coated the prepared slurry on aluminum foil by casting method, and dried it in a vacuum oven at 120°C for 2 hours to obtain a graphene-coated aluminum foil current collector. The number of graphene sheets used is 4-7 layers, with good crystallinity and a specific surface area of ​​about 380 m 2 / g, the electrical conductivity is about 3520 S / m, and the thickness of the graphene coating is 8 μm.

[0041] Secondary coating:

[0042] (1) Mix graphene and s...

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Abstract

The invention belongs to the technical field of application of electrochemistry, and discloses an cathode material for a high-capacity graphene lithium sulphur battery and a preparation method of the cathode material. The cathode material comprises a graphene film coated for one time and a graphene/sulphur composite material coated for two times. The preparation method comprises the following steps: sufficiently mixing graphene with slurry to obtain graphene dispersed slurry, coating an aluminium foil with the graphene dispersed slurry, drying in a vacuum drying box to obtain a current collector coated for one time, mixing graphene with slurry to obtain the graphene/sulphur composite material, mixing, stirring and pulping the graphene/sulphur composite material, a binder and a conductive agent, coating the current collector coated for one time with the slurry, and drying in vacuum. According to the invention, the problem of being poor in cohesiveness between the slurry and the current collector is solved; the electrical conductivity between an active substance and the current collector is increased; migration of polysulfide is effectively relieved; the utilization rate of active sulphur is increased; the cost is low; and the cathode material can be easily applied in cathode materials of lithium sulphur secondary batteries massively.

Description

technical field [0001] The invention belongs to the technical field of electrochemical applications, and in particular relates to a high-capacity graphene lithium-sulfur battery cathode material and a preparation method thereof. Background technique [0002] With the rapid development of electric vehicles and mobile electronic devices, people's requirements for the energy density of lithium-ion batteries are getting higher and higher. Lithium-sulfur batteries have very obvious advantages in terms of energy density. Compared with other battery systems, sulfur has a high theoretical specific capacity of 2800 Wh / kg (1675mAh / g). In addition, sulfur reserves are abundant, the cost is low, and the sulfur electrode material itself and the use process seldom produce harmful substances to the environment. Therefore, lithium-sulfur batteries are high-energy-density secondary batteries with great development potential and application prospects. However, lithium-sulfur batteries ...

Claims

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Application Information

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IPC IPC(8): H01M4/583H01M4/36
CPCH01M4/1393H01M4/362H01M4/5835Y02E60/10
Inventor 陈欣李星蔡京易王春雨文怀梁易江平赵成龙王瑛
Owner SHANDONG YUHUANG NEW ENERGY TECH
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