One-dimensional nitrogen-doped double-layer carbon shell/sulfur composite positive electrode material for lithium-sulfur battery and preparation method thereof

A lithium-sulfur battery and cathode material technology, which is applied in battery electrodes, lithium storage batteries, and positive electrodes to achieve high rate performance, novel structure, and long cycle life.

Inactive Publication Date: 2018-02-23
GUANGZHOU HKUST FOK YING TUNG RES INST +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, there is still relatively little research on high-rate lithium-sulfur batteries. Since electric vehicles and unmanned aircraft require high power at an instant when starting and accelerating, this is a problem that lithium-sulfur batteri

Method used

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  • One-dimensional nitrogen-doped double-layer carbon shell/sulfur composite positive electrode material for lithium-sulfur battery and preparation method thereof
  • One-dimensional nitrogen-doped double-layer carbon shell/sulfur composite positive electrode material for lithium-sulfur battery and preparation method thereof
  • One-dimensional nitrogen-doped double-layer carbon shell/sulfur composite positive electrode material for lithium-sulfur battery and preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0029] The first step: the FeCl 3 and NH 4 h 2 PO 4 After mixing according to the molar ratio of 28:1, put it into the hydrothermal reaction kettle, heat it at 240 degrees for 20 hours, filter and wash it after cooling to room temperature, and obtain the hollow Fe 2 o 3 Rod precursor; the resulting Fe 2 o 3 The precursor was dispersed into a 0.5g concentration of dopamine aqueous solution and stirred for 2 hours, filtered and cleaned, and vacuum dried to obtain a PDA@Fe2O3 composite material;

[0030] The second step: put the obtained composite material into a mixed gas of argon and ammonia (Ar:NH 3 =1:1) in a tube furnace with a gas flow rate of 50 ml / min, high temperature carbonization for 1 hour at a temperature of 1000°C, and then the product obtained was etched in an aqueous hydrochloric acid solution with a concentration of 0.1 moles per liter for 4 hours, cleaned After filtration and vacuum drying, a one-dimensional nitrogen-doped double-layer carbon shell was ob...

Embodiment 2

[0034] The first step: except that it is heated for 30 hours under the condition of 220 degrees, other is the same as embodiment one;

[0035] The second step: put the obtained composite material into a tube furnace with nitrogen gas, the gas flow rate is 300 ml / min, carbonize at high temperature for 2 hours, the temperature is 1000 ° C, and then the obtained product is put into a concentration of 0.1 moles per It was etched in 1 liter of hydrochloric acid aqueous solution for 4 hours, cleaned and filtered, and then vacuum-dried to obtain a one-dimensional nitrogen-doped double-layer carbon shell.

[0036] Step 3: Mix commercial sulfur powder and one-dimensional nitrogen-doped double-layer carbon shell according to the weight ratio of 2:1, then put it into a closed container, vacuumize to 300Pa, and then use 2 degrees / min The heating rate was increased to 200 degrees, kept for 12 hours, then cooled to 160 degrees, kept for 12 hours, and rapidly cooled to room temperature to ob...

Embodiment 3

[0039] The first step: except that it is heated for 10 hours under the condition of 250 degrees, it is the same as embodiment one;

[0040] Step 2: Put the obtained composite material into a tube furnace with protective gas, carbonize at high temperature for 2 hours at a temperature of 1200°C, then put the obtained product into an appropriate concentration of hydrochloric acid solution for etching for 4 hours, wash and filter After vacuum drying, a one-dimensional nitrogen-doped double-layer carbon shell was obtained.

[0041] Step 3: Mix commercial sulfur powder and one-dimensional nitrogen-doped double-layer carbon shell at a ratio of 3:1, and then put it in a closed container. After vacuuming, the vacuum degree is 100 Pa, and the temperature is 2 degrees / min. Slowly increase the rate to 250°C, hold for 20 hours, then cool down to 155°C, hold for 10 hours, and rapidly cool to room temperature to obtain a one-dimensional nitrogen-doped double-layer carbon shell / sulfur composi...

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Abstract

The invention discloses a one-dimensional nitrogen-doped double-layer carbon shell/sulfur composite positive electrode material and a preparation method thereof. According to the material, an elongated double-layer carbon shell is prepared from a nitrogen-doped carbon material, and elemental-sulfur nanoparticles are dispersed in the carbon shell. According to the preparation method, the double-layer carbon shell is used as a sulfur-fixing precursor, and elemental sulfur is uniformly disperses in the double-layer carbon shell in the form of nanoparticles in virtue of a vacuum molten salt process. The size and content of sulfur particles are controlled via the one-dimensional size of the carbon shell, so the usage rate of sulfur is increased; the contact area between sulfur and an electrolyte is increased via the double-layer carbon shell, so the utilization rate of sulfur is improved; nitrogen-doped graphitized carbon is used for improving the electric conductivity of sulfur; and the loss of polysulfides and the cycle performance of the electrode material are improved in virtue of the hermeticity of the carbon shell, usage of a double-layer structure and chemical coordination between nitrogen and sulfur. The preparation method is simple in process and easy to operate; and the prepared composite positive electrode material has excellent properties, high specific discharge capacity, large rate and good long cycle performance, and has good application prospects in fields like mobile communications, portable electronic devices, energy storage devices, unmanned aerial vehicles and electric vehicles.

Description

technical field [0001] The invention relates to the technical field of battery cathode materials, in particular to a one-dimensional nitrogen-doped double-layer carbon shell / sulfur lithium-sulfur battery composite cathode material with high specific capacity, long cycle life and high rate performance. The invention also relates to a method for the preparation of said material. Background technique [0002] With the rapid development of related industries such as mobile communications, portable electronic devices, electric vehicles and energy storage devices, higher and higher requirements are placed on battery performance, especially specific capacity, energy density, cycle life and rate performance. . Therefore, it is of great strategic significance to develop new lithium-ion secondary batteries with high performance, low cost and environmental friendliness. The performance and price of cathode materials are the bottlenecks that restrict the further development of lithium...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M10/052B82Y30/00
CPCB82Y30/00H01M4/366H01M4/38H01M4/625H01M10/052H01M2004/021H01M2004/028Y02E60/10
Inventor 徐辉覃旭松陈国华
Owner GUANGZHOU HKUST FOK YING TUNG RES INST
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