A kind of preparation method of wool spherical carbon/sulfur composite microsphere material and lithium-sulfur battery

Abstract

The invention discloses a method for preparing carbon / sulfur composite micro-sphere materials in the shapes of woolen yarn balls and a lithium-sulfur battery. Carbon micro-spheres in the shapes of woolen yarn balls can be prepared by the aid of electrostatic spinning processes, and sulfur can be loaded in the carbon micro-spheres to prepare carbon / sulfur composite micro-spheres for positive electrode materials for lithium / sulfur ion batteries. The method for preparing the carbon / sulfur composite micro-spheres includes stirring selected fibrous carbon materials or fibrous carbon precursors andbinders in solvents in a shear-type manner and uniformly dispersing the fibrous carbon materials or the fibrous carbon precursors and the binders in the solvents; carrying out electrostatic spinning treatment to obtain carbon precursor micro-spheres in the shapes of woolen yarn balls; carrying out carbonization treatment to obtain the carbon micro-spheres in the shapes of the woolen yarn balls. The obtained carbon micro-spheres in the shapes of the woolen yarn balls and the elemental sulfur are heated in a tube furnace to obtain the carbon / sulfur composite micro-sphere materials, and the carbon / sulfur composite micro-sphere materials can be used as the positive electrode materials for the lithium-sulfur battery. The method and the lithium-sulfur battery have the advantages that the positive electrode materials prepared from the carbon and composite materials for the lithium / sulfur ion batteries are excellent in morphology and performance as compared with conventional carbon materials and are high in first specific discharge capacity and excellent in capacity retention ratio when used as the positive electrode materials for the lithium-sulfur battery; the method is simple, feasibleand environmentally friendly, is low in cost and has an excellent application prospect.

Description

technical field [0001] The invention belongs to the technical field of electrode materials, and more specifically, relates to a preparation method of a yarn spherical carbon / sulfur composite microsphere material and a lithium-sulfur battery. Background technique [0002] With the increasing demand for energy consumption in the world, the oil resources that can be developed and utilized are increasingly depleted, while the environmental pollution is becoming more and more serious. Therefore, the use of electrochemical energy storage technology to store and reuse clean solar energy and wind energy is undoubtedly the solution to this problem in the 21st century. In addition, mobile electronic devices and electric vehicles that affect people's lives also put forward higher requirements for future electrochemical energy storage technology. All of these require safe, low-cost, high-energy-density and long-life secondary batteries to be realized. Among many energy storage methods,...

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Problems solved by technology

[0003] Lithium-ion batteries use graphite materials as the negative electrode, and lithium-containing metal oxides such as lithium iron phosphate, lithium cobalt oxide, and lithium manganese oxide as the positive electrode, and use the "rocking chair effect" of lithium ions between the positive and negative electrodes to contribute capacity. The theoretical specific capacity of the secondary lithium-ion battery itself is nearly 300mAh / g. Even so, it is difficult to meet the requirements of the secondary battery that people need. Energy lithium-sulfur battery has become the current research and development object

[0004] Lithium-sulfur batteries use elemental sulfur as the positive electrode and metallic lithium as the negative electrode. The theoretical specific capacity of elemental sulfur reaches 1680mAh / g, and elemental sulfur is cheap, rich in resources, and environmentally friendly. To a certain extent, it can replace lithium-ion batteries. However, the actual specific capacity of lithium-sulfur batteries is much smaller than the theoretical specific capacity, thus limiting its large-scale application.

The main reason for this phenomenon is that during the charging and discharging cycle of lithium-sulfur batteries, polysulfides are easily soluble in the electrolyte, and at the end of the cycle, not all of them are converted into final products, resulting in the loss of effective substances The "shuttle effect" caused by the dissolution of polysulfides greatly reduces the capacity of lithium-sulfur batteries

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