Preparation method of positive electrode material for lithium-sulfur battery

Abstract

The invention discloses a preparation method of a positive electrode material for a lithium-sulfur battery. The method comprises the following steps of (1) preparing monodisperse polystyrene microspheres through a dispersion polymerization method; (2) preparing hollow silica microspheres; (3) synthesizing bimetallic oxide double-layer nano mesoporous microspheres; and (4) preparing a nickel-cobaltbimetallic oxide double-layer nano mesoporous microspheres / nano carbon / sulfur composite positive electrode material. Through a process of doping with nano sulfur and nano carbon black through ball-milling and hot melting methods, the nano carbon black is mixed in the sulfur doping process, so that the defects that the positive electrode material for the lithium-sulfur battery in the prior art islow in sulfur load, obvious in volume expansion effect and unstable in electrochemical properties are overcome.

Description

technical field [0001] The technical solution of the present invention relates to a preparation method of a lithium-sulfur battery positive electrode material with high specific capacity, in particular to a method for preparing a double-layer double-metal oxide hollow microsphere material by a template method, and then preparing sulfur by using a ball milling and hot melting method. The invention discloses a method for nanometer carbon / double-layer bimetallic oxide composite lithium-sulfur battery cathode material, which belongs to the field of material chemistry. Background technique [0002] With the continuous development and progress of human society, non-renewable resources such as coal, oil, and natural gas are becoming increasingly exhausted, but human demand for energy is increasing day by day. Energy is the basis for the normal operation of the entire human society. Traditional energy has been unable to meet the needs of human society. In the long-term development, ...

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Problems solved by technology

[0004] Although the prospect of lithium-sulfur batteries is very bright, after so long research, lithium-sulfur batteries are still in the laboratory stage and cannot be commercialized, mainly because of the following difficult problems:

[0005] 1. Elemental sulfur is an electronic and ion insulator, and its conductivity at room temperature is only 5*10~30S / cm, and its electrochemical activity is not high as a positive electrode material

[0006] 2. The density of elemental sulfur and sulfide, the charge and discharge product, is different, and serious volume expansion will occur, and the volume expansion rate is about 76%.

And repeated volume changes during charging and discharging will eventually destroy the physical structure of the battery and cause the entire battery system to collapse

[0007] 3. The unique shuttle effect of lithium-sulfur batteries, that is, the polysulfides generated during the charging and discharging process of the battery shuttle back and forth between the positive and negative electrodes, causing the battery to self-discharge.

The shuttle effect of lithium-sulfur batteries will affect the normal battery charge and discharge process, reduce the specific capacity of the battery and the cycle stability of the battery

[0008] 4. The polysulfides generated during the charging and discharging of lithium-sulfur batteries will dissolve in the currently used electrolyte solution, resulting in the loss of active materials of the positive electrode material and reducing the overall electrochemical performance of the battery

This patented technology has improved and improved the performance of the cathode material to a certain extent, but there are still some shortcomings: the capacity of the cathode material is limited, the loading rate of the active material is not high, the volume expansion effect is not significantly suppressed, and the overall electrochemical performance is not high.

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