Nanometer titanium dioxide composite nitrogen-doped carbon nanofibers and preparation method and application thereof

A technology of nano-titanium dioxide and nitrogen-doped carbon, which is applied in secondary batteries, electrochemical generators, electrical components, etc., can solve the problems of slow battery reaction kinetics, affecting battery performance, and volume expansion of positive electrode materials, etc. Lithium sulfide shuttle effect, stable cycle performance, and the effect of increasing adsorption sites

Active Publication Date: 2018-12-18
SOUTH CHINA NORMAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, the research on lithium-sulfur batteries has gone through many years. Although many achievements have been made and a deeper understanding of its reaction mechanism has been obtained, there are still problems that are difficult to solve.
These problems are mainly divided into two aspects: (1) in the cathode region, the insoluble and insulating S and Li 2 S will lead to slow battery reaction kinetics, and will destroy the structure of the positive electrode material of the battery, resulting in volume expansion of the posi...

Method used

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  • Nanometer titanium dioxide composite nitrogen-doped carbon nanofibers and preparation method and application thereof
  • Nanometer titanium dioxide composite nitrogen-doped carbon nanofibers and preparation method and application thereof
  • Nanometer titanium dioxide composite nitrogen-doped carbon nanofibers and preparation method and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] A nano-titanium dioxide composite nitrogen-doped carbon nanofiber is prepared by the following method:

[0037] (1) Prepare 18 mL of N,N-dimethylformamide solution containing acrylonitrile, in which the mass volume concentration of acrylonitrile is 0.0756 g·ml-1 ;

[0038] (2) Add 2.5 mL of tetrabutyl titanate to the solution obtained in (1) and continue stirring for 10 min to obtain a uniformly dispersed white emulsion;

[0039] (3) Pour the precursor solution obtained in (2) into a 20 mL syringe, install a No. 20 needle and place it in the electrospinning device; the conditions for electrospinning are: the electric field strength is 1.67 KV cm -1 , the heating temperature is 60°C, and the advancing speed is 1.2 mL·h -1 advance speed.

[0040] (4) Put the precursor fiber obtained in (3) in a corundum crucible, and heat it in a tube furnace at 5°C min -1 The heating rate is heated to 280 ° C for 2 h; -1 The heating rate was heated to 700°C for 2 h for carbonization;...

Embodiment 2

[0042] The preparation process of the nano-titanium dioxide composite nitrogen-doped carbon nanofiber provided in this example is the same as that in Example 1, except that the carbonization temperature used is 750°C.

[0043] Example 2

[0044] The preparation process of the nano-titanium dioxide composite nitrogen-doped carbon nanofiber provided in this example is the same as in Example 1, except that the tetrabutyl titanate used is 2 mL, that is, the tetrabutyl titanate in the white emulsion in step (2) The volume fraction of butyl ester is 11.11%.

Embodiment 3

[0046] The preparation process of the nano-titanium dioxide composite nitrogen-doped carbon nanofiber provided in this example is the same as in Example 1, except that the tetrabutyl titanate used is 3 mL, that is, the tetrabutyl titanate in the white emulsion in step (2) The volume fraction of butyl ester is 16.67%.

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Abstract

The invention discloses nanometer titanium dioxide composite nitrogen-doped carbon nanofiber and a preparation method and application thereof. The nanofibers are prepared by the following steps: S1. preparing a DMF precursor solution of polyacrylonitrile; 2, uniformly mixing tetrabutyl titanate and the precursor solution to obtain an emulsion; and 3, electrospinning the emulsion to obtain precursor fibers; then performing pyrolysis and carbonization on the precursor fibers to obtain the nanofibers. The surface of the nano fiber provided by the invention is a balsam pear-shaped fold, and afterbeing prepared as a positive electrode of a lithium sulfide battery, the conductivity of the sulfide positive electrode can be improved and the lithium polysulfide shuttle effect can be reduced; Because of its unique three-dimensional self-supporting balsam pear fiber structure, it not only increases the adsorption sites of lithium polysulfide, but also greatly alleviates the volume expansion of the battery. 97% capacity can be maintained after 100 cycles at 0.2 C current density after the nanofibers are made into a three-dimensional self-supporting current collector, and the nanofibers have stable cycling performance and high specific capacity.

Description

technical field [0001] The invention relates to the technical field of lithium-sulfur batteries, and more specifically relates to a nano-titanium dioxide composite nitrogen-doped carbon nanofiber and a preparation method and application thereof. Background technique [0002] Due to the impact of the energy crisis and the concept of green development, energy storage devices with high specific capacity and long cycle life have received more and more attention. Lithium-sulfur batteries have a high energy density (2600 W h kg -1 ) and high specific capacity (1675mAh g -1 ) is considered to be one of the next-generation low-cost secondary batteries that can replace lithium-ion batteries. [0003] The current research on lithium-sulfur batteries has gone through many years. Although many achievements have been made and a deeper understanding of its reaction mechanism has been obtained, there are still problems that are difficult to solve. These problems are mainly divided into ...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/485H01M4/583H01M4/62H01M10/0525
CPCH01M4/362H01M4/485H01M4/583H01M4/625H01M10/0525Y02E60/10
Inventor 商超群张旭梓黄兰艳王新
Owner SOUTH CHINA NORMAL UNIVERSITY
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