Nitrogen-containing heterocyclic organic sulfur electrolyte as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of lithium-sulfur batteries, and discloses a nitrogen heterocyclic ring organic sulfur electrolyte as well as a preparation method and application thereof. The electrolyte comprises an ether solvent, a lithium salt, an initiator and a nitrogen heterocyclic organic sulfur additive. The additive can generate high-activity azacyclo-S. Free radicals in the charging and discharging process, in-situ covalent bonding is carried out on the high-activity azacyclo-S. Free radicals and sulfur species through intermolecular recombination, and organic polysulfide is generated, so that a positive electrode reaction path is reconstructed, generation and shuttling of lithium polysulfide (LiPS) are fundamentally inhibited, and positive electrode interface ion / electron transmission is optimized. Meanwhile, the additive can be induced to form a stable SEI layer rich in organic lithium salt on the surface of the lithium negative electrode, so that the growth of lithium dendrites is effectively inhibited, and the interface stability of the negative electrode is improved. According to the invention, collaborative optimization of a positive electrode interface and a negative electrode interface of the lithium-sulfur battery is realized through a single additive, the electrolyte system has excellent liquid-state and solid-state battery compatibility, and the cycle life, the specific capacity and the energy density of the battery can be remarkably improved.

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