Composite material for lithium-sulfur battery positive electrode and preparation method of composite material

Abstract

The invention relates to a composite material for a lithium-sulfur battery positive electrode and a preparation method of the composite material. Prevulcanization polymerization reaction is performedon diaminomaleonitrile and sulfur under a high temperature, sulfur eight-ring is opened under the high temperature to form a free radial, cyan cyclotrimerization is catalyzed to form a covalent triazine framework, sulfur is fixed on a polymer framework in a C-S bond form, and more sulfur is loaded onto the covalent triazine framework by a melting method. The nitrogen atom-doped covalent triazine framework has favorable conductivity, and the conductivity of the sulfur positive electrode can be effectively improved; the damage of volume expansion and shrinkage of the sulfur positive electrode tothe positive electrode can be reduced during the charge-discharge process by the stable covalent triazine framework, the sulfur fixed in the material in a chemical bond form can be used for effectively preventing a shuttle effect of lithium polysulfide, and excellent cycle property and rate performance of the composite material when used for the lithium-sulfur battery can be shown.

Description

technical field [0001] The invention relates to the field of chemical power sources, in particular to a composite material used for the positive electrode of a lithium-sulfur battery and a preparation method thereof. Background technique [0002] With the rapid development of modern science and technology, lithium-ion batteries are gradually applied to large devices (such as electric vehicles) from small portable devices. However, traditional lithium-ion batteries can no longer meet people's demand for high-endurance chemical energy storage devices. The theoretical specific capacity of elemental sulfur is 1675mAh g -1 , the energy density is as high as 2600Wh·kg -1 , and it has the advantages of abundant reserves, environmental friendliness and low price. Therefore, lithium-sulfur batteries are favored by researchers and are considered to be one of the viable alternatives to current commercial lithium-ion batteries. [0003] Despite so many advantages of lithium-sulfur b...

AI Technical Summary

Problems solved by technology

Although these composite materials have improved cycle performance to a certain extent, these materials have weak binding force to sulfur or lithium polysulfide, and lithium polysulfide still has a shuttle effect after a long cycle.

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