Preparation method of graphene nanoscroll/sulfur composite material and application of graphene nanoscroll/sulfur composite material

A composite material, graphene technology, applied in electrode carriers/current collectors, electrical components, electrochemical generators, etc., can solve the problems of poor cycle stability of lithium-sulfur batteries, affecting the utilization of active materials, and increasing the internal impedance of batteries, etc. Achieve good cycle stability, improve utilization, and improve cycle stability.

Active Publication Date: 2015-11-11
HARBIN INST OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, elemental sulfur is an insulator of electrons and ions, which greatly increases the internal impedance of the battery and produces a large polarization, which seriously affects the utilization of active materials.
In addition, lithium polysulfide (Li 2 S x , 3≤x≤6) will be dissolved in the electrolyte to cause the loss of active materials, and the dissolved lithium polysulfide will shuttle back and forth between the positive and negative electrodes, and react with the metallic lithium negative electrode, resulting in lower Coulombic efficiency and accelerated lithium corrosion , these problems lead to poor cycle stability of lithium-sulfur batteries

Method used

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  • Preparation method of graphene nanoscroll/sulfur composite material and application of graphene nanoscroll/sulfur composite material
  • Preparation method of graphene nanoscroll/sulfur composite material and application of graphene nanoscroll/sulfur composite material
  • Preparation method of graphene nanoscroll/sulfur composite material and application of graphene nanoscroll/sulfur composite material

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Embodiment 1

[0038] 1), the preparation of pre-oxidized graphite:

[0039] Add 39mL of concentrated sulfuric acid (98%) into a three-necked flask, then weigh 2.5g of potassium persulfate and 2.5g of phosphorus pentoxide and add them to the three-necked flask successively, mix well; then add 5g of natural flake graphite powder (325 mesh), Then place it in a constant temperature water bath and react for 6 hours under stirring at 80°C; slowly pour the reactant into a beaker filled with 700ml of deionized water for dilution, transfer the diluted liquid to a Buchner funnel for filtration, and wash until the filtrate into neutral. The obtained filter cake was dried under vacuum at 100° C. for 10 h, and the obtained solid matter was pre-oxidized graphite.

[0040] 2), the preparation of graphite oxide:

[0041]Weigh 2.5g of pre-oxidized graphite and 1.25g of sodium nitrate powder into a round-bottomed flask filled with 57.5mL of concentrated sulfuric acid (98%), slowly add 7.5g of potassium per...

Embodiment 2

[0050] 1), the preparation of pre-oxidized graphite:

[0051] Mix 3g of natural flake graphite (200 mesh) with 2.5g of potassium persulfate and 2.5g of phosphorus pentoxide into a three-necked flask filled with 50mL of concentrated sulfuric acid (98%), mix well under magnetic stirring conditions, and then place at constant temperature In a water bath, react at 80°C for 6 hours; after the reaction, dilute with deionized water, then filter and wash with a Buchner funnel until the filtrate becomes neutral. The filter cake was dried under vacuum at 80° C. for 20 h, and the obtained solid matter was pre-oxidized graphite.

[0052] 2), the preparation of graphite oxide:

[0053] Weigh 2.5g of pre-oxidized graphite and 1.25g of sodium nitrate powder into a round-bottomed flask filled with 57.5mL of concentrated sulfuric acid (98%). Slowly add 10g of potassium permanganate in an ice-water bath to control the temperature of the reaction system. After reacting for 3 hours at 20°C, rai...

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Abstract

The invention discloses a preparation method of a graphene nanoscroll / sulfur composite material and an application of the graphene nanoscroll / sulfur composite material. The preparation method of the graphene nanoscroll / sulfur composite material is as follows: with a graphene nanoscroll which is modified with nanoparticles on the surface as matrix, the graphene nanoscroll / sulfur composite material is obtained in a melt sulfur-injection manner; agglomeration of graphene sheets is effectively inhibited by the graphene with a wound structure; the pore structure in the graphene is beneficial to storage of sulfur; the conductivity of an electrode is further improved by excellent electrical conductivity of the graphene; and the active material is fully utilized. In addition, intense interaction exists between metal oxide nanoparticles which are modified on the graphene surface and a discharge intermediate product lithium polysulfide; and dissolution of the polysulfide can be effectively inhibited, so that the material shows high specific capacity and good cycling stability; the method is simple to operate and low in cost; and large-scale production is easy to realize.

Description

technical field [0001] The invention relates to a preparation method of a lithium-sulfur battery positive electrode material, in particular to a preparation method of a graphene nano-volume / sulfur composite material for a lithium-sulfur battery. Background technique [0002] With the depletion of petroleum resources and the increasing environmental pollution, countries around the world are paying more and more attention to the storage and reuse of clean energy such as wind energy and solar energy, as well as the development of electric vehicles, which puts forward a higher energy density for the battery system. Requirements, while the lithium-ion battery currently dominant in the market is difficult to meet the demand due to the limitation of its theoretical capacity. In contrast, the lithium-sulfur battery has a theoretical energy density of 2600Wh / kg. Its positive electrode material, elemental sulfur, is abundant in sources, cheap in price, and environmentally friendly. It...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/38H01M4/66H01M4/133H01M10/0525
CPCH01M4/133H01M4/38H01M4/663H01M10/0525Y02E60/10
Inventor 左朋建张玮尹鸽平高云智
Owner HARBIN INST OF TECH
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