Nickel-cobalt-sulfur hollow sphere used as lithium-sulfur battery positive electrode, and preparation method and application thereof

Abstract

The invention discloses a nickel-cobalt-sulfur hollow sphere used as a lithium-sulfur battery positive electrode, and a preparation method thereof and an application thereof in the preparation of a lithium-sulfur battery. The preparation method comprises the following steps: dissolving cobalt nitrate hexahydrate, nickel nitrate hexahydrate, potassium peroxydisulfate or ammonium peroxodisulfate, ammonium fluoride and sodium acetate in deionized water, performing stirring, adding a nano-silica sphere, and performing ultrasonic dispersion; heating and reacting the obtained suspension, washing theobtained reaction product, and drying the washed reaction product; and adding obtained precursor powder to deionized water, performing ultrasonic dispersion, adding sodium sulfide nonahydrate to theobtained dispersion, heating and reacting the obtained mixed solution, washing the obtained reaction product, and drying the washed reaction product to obtain black nickel-cobalt-sulfur nano-hollow sphere powder. A nickel-cobalt-sulfur nano-particle prepared by using the nickel-cobalt-sulfur hollow nano-sphere prepared through a simple hydrothermal technology in a one-step manner as a sulfur fixing material has a good prospect as a lithium-sulfur battery positive electrode supporting material, and improves the cycle performances of the lithium-sulfur battery. The preparation method has the advantages of simplicity, easiness in operation, safety, environmental protection, low cost, and suitableness for large-scale production.

Description

technical field [0001] The invention relates to a nickel-cobalt-sulfur hollow sphere used as a positive electrode of a lithium-sulfur battery, a preparation method and application thereof, and belongs to the technical field of preparation of ion battery electrode materials. Background technique [0002] With the increasing demand for energy in the current society and the depletion of traditional fossil energy, this puts forward higher requirements for the efficient use and storage of energy. During this period, lithium-ion batteries have entered people's lives as a high-load, portable device. Lithium-sulfur batteries have a high theoretical specific capacity (1675mAh / g), which is far higher than the current graphite-based lithium battery. ion battery (372mAh / g), thus becoming a promising next-generation energy storage device. However, in addition to the disadvantages of traditional lithium-ion batteries, lithium-sulfur batteries also have a series of problems that need to b...

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Problems solved by technology

However, in addition to the disadvantages of traditional lithium-ion batteries, lithium-sulfur batteries also have a series of problems that need to be solved urgently: metal lithium will gradually generate lithium dendrites during charging and discharging, which will eventually pierce the separator and cause short circuit of the battery; due to the use of metal lithium It is very sensitive to moisture and air, so it has high requirements on the sealing performance of the battery; the discharge intermediate product lithium polysulfide can be dissolved in the electrolyte, and reacts with the metal lithium as the electrolyte reaches the negative electrode during the charging and discharging process, causing the battery The performance is seriously attenuated; the conductivity of the sulfur element is extremely low, which makes it difficult to fully charge and discharge, and makes the internal resistance of the battery large; the density of the final product lithium sulfide is lower than that of the sulfur element, so the volume of the positive electrode expands during the discharge process, destroying the battery structure

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