Boron/nitrogen double-doped porous carbon nanosheet and lithium-sulfur battery positive electrode material thereof

A cathode material, lithium-sulfur battery technology, applied in battery electrodes, lithium storage batteries, positive electrodes, etc., can solve the problems of volume expansion of electrode materials, improvement of sulfur cathode conductivity, etc., to achieve improved conductivity, excellent cycle performance, strong Lewis The effect of acid-base action

Pending Publication Date: 2020-05-19
NANCHANG UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The present invention aims at the technical defects of the prior art, and provides a boron / nitrogen double-doped porous carbon nanosheet and its lithium-sulfur battery positive electrode material to solve the problem that the conductivity of the sulfur positive electrode needs to be improved in the lithium-sulfur battery, and the electrode The technical problem of the volume expansion phenomenon of the material

Method used

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  • Boron/nitrogen double-doped porous carbon nanosheet and lithium-sulfur battery positive electrode material thereof
  • Boron/nitrogen double-doped porous carbon nanosheet and lithium-sulfur battery positive electrode material thereof
  • Boron/nitrogen double-doped porous carbon nanosheet and lithium-sulfur battery positive electrode material thereof

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Embodiment 1

[0034] A method for preparing boron / nitrogen double-doped porous carbon nanosheets and a positive electrode material for a lithium-sulfur battery, comprising the following steps:

[0035] Step 1, preparation of boron / nitrogen double-doped porous carbon nanosheets:

[0036] Weigh 80mmol (4.8g) of urea, 2.5mmol (0.1545g) of boric acid and 0.25mmol (0.5g) of polyethylene glycol-2000, add to 50mL of deionized water and stir evenly, evaporate and dry the resulting solution to obtain a white powder; Put the obtained white powder precursor into a tube furnace, heat up to 900°C at a rate of 5°C / min in an argon atmosphere, carbonize for 2 hours, and finally cool to room temperature to obtain boron / nitrogen double-doped porous carbon nanosheets;

[0037] Step 2, compounding the boron / nitrogen double-doped porous carbon nanosheets obtained in step 1 with simple sulfur:

[0038] Mix boron / nitrogen double-doped porous carbon nanosheets and sulfur simple substance at a mass ratio of 1:4, a...

Embodiment 2

[0040] A method for preparing boron / nitrogen double-doped porous carbon nanosheets and a positive electrode material for a lithium-sulfur battery, comprising the following steps:

[0041] Mix boron / nitrogen double-doped porous carbon nanosheets obtained in step 1 of Example 1 with sulfur element in a mass ratio of 1:3, grind to obtain a mixture of boron / nitrogen double-doped porous carbon nanosheets and sulfur, and place in a crucible Put the crucible containing the above mixture into a polytetrafluoroethylene reactor in an argon atmosphere and seal it; transfer the sealed reactor to an oven at 155°C and keep it warm for 12 hours; cool to room temperature to obtain lithium Sulfur battery cathode material (S / B-N-CNSs-2), the actual sulfur content measured by thermogravimetric test is ~76.1wt%.

Embodiment 3

[0043] A method for preparing boron / nitrogen double-doped porous carbon nanosheets and a positive electrode material for a lithium-sulfur battery, comprising the following steps:

[0044] Mix boron / nitrogen double-doped porous carbon nanosheets obtained in step 1 of Example 1 with sulfur element in a mass ratio of 1:2, grind to obtain a mixture of boron / nitrogen double-doped porous carbon nanosheets and sulfur, and place in a crucible Put the crucible containing the above mixture into a polytetrafluoroethylene reactor in an argon atmosphere and seal it; transfer the sealed reactor to an oven at 155°C and keep it warm for 12 hours; cool to room temperature to obtain lithium Sulfur battery cathode material (S / B-N-CNSs-3), the actual sulfur content measured by thermogravimetric test is ~67.0wt%.

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Abstract

The invention provides a boron/nitrogen double-doped porous carbon nanosheet and a lithium-sulfur battery positive electrode material thereof. According to the technical scheme, urea, boric acid and polyethylene glycol serve as raw materials, the boron/nitrogen double-doped porous carbon nanosheet is prepared through high-temperature carbonization, and the prepared boron/nitrogen double-doped porous carbon nanosheet is of a graphene-like two-dimensional sheet structure and has a high specific surface area and rich micropores and mesopores; on the basis, the boron/nitrogen double-doped porous carbon nanosheet is used as a carrier, and the positive electrode materials with different sulfur contents are prepared by a melt diffusion method. In the lithium-sulfur battery positive electrode material provided in the invention, the unique two-dimensional structure of the boron/nitrogen double-doped porous carbon nanosheet is beneficial to promoting rapid transfer of electrons and relieving volume expansion of a sulfur electrode, and boron/nitrogen doped atoms have a relatively strong Lewis acid-base effect on lithium polysulfide, so that the shuttle effect of the electrode can be effectively inhibited, and relatively high specific capacity and excellent cycle performance are shown.

Description

technical field [0001] The invention relates to the technical field of new energy materials, in particular to a boron / nitrogen double-doped porous carbon nanosheet and its lithium-sulfur battery cathode material. Background technique [0002] In recent years, the new energy automobile industry has continued to develop in my country, which has put forward higher requirements for the energy density of power batteries. The development of new high energy density secondary battery system has become the key. Lithium-sulfur battery is a secondary battery constructed with sulfur as the positive electrode and metal lithium as the negative electrode. Its theoretical energy density can reach 2600Wh / kg, which is much higher than the energy density of commercial lithium-ion batteries. It is considered to be the next-generation power battery backup. choose one. However, limited by the insulation of sulfur, the volume expansion of electrode materials during the reaction process, and the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B32/15H01M4/36H01M4/38H01M4/62H01M10/052H01M4/02
CPCC01B32/15H01M4/364H01M4/38H01M4/625H01M4/628H01M10/052H01M2004/021H01M2004/028Y02E60/10
Inventor 张泽熊冬根杨震宇
Owner NANCHANG UNIV
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