A method for preparing sulfur-based positive electrode materials using mesh-like porous nano-lanthanum oxide

Abstract

The invention relates to a method for preparing a positive electrode of a lithium-sulfur battery from an active material, and belongs to the field of material chemistry. The method uses spray drying technology to prepare porous network nano-lanthanum oxide, and then realizes the composite of porous network nano-lanthanum oxide and sulfur through hydrothermal reaction to obtain a rare earth sulfur-based positive electrode material. After being assembled into a battery, the first discharge capacity is as high as 1095mAh / g . The method has high yield and industrial feasibility, and the nano-lanthanum oxide in the obtained rare earth sulfur-based cathode material can ensure its high conductivity to improve the transmission rate of electrons and ions, and adsorb soluble polysulfides; the network porous structure can not only provide rich The active site can also effectively cover the sulfur.

Description

technical field [0001] The invention relates to a method for preparing a positive electrode of a lithium-sulfur battery from an active material, and belongs to the field of material chemistry. Background technique [0002] Rechargeable batteries are undoubtedly one of the most important basic components closely related to human activities, and have been widely used in portable electronic products, such as mobile phones, laptops, cars, wearable sensors and medical equipment, etc., and people are very concerned about their performance Higher and higher demands have been put forward. At present, traditional commercial lithium-ion batteries are limited by their own theoretical specific capacity (300mAh / g) and safety issues, and it is difficult to meet the quality requirements of lithium-ion batteries for practical applications. Therefore, it is of great strategic significance to develop next-generation lithium-ion secondary batteries with high energy density, environmental prot...

AI Technical Summary

Problems solved by technology

First, since elemental sulfur acts as an insulator of electrons and ions at room temperature, the transmission efficiency of electrons and ions is low, which reduces the Coulombic efficiency; second, the reduction intermediate "polysulfide" is dissolved in the electrolyte, resulting in The severe shuttling effect results in a shortened cycle life of Li-S batteries; third, the initial lithiation of sulfur forms long-chain lithium polysulfides (4≤n≤8), which are soluble in organic electrolytes and can pass through the separator to the anode side

Subsequently, it can be further lithiated into low-order short-chain lithium polysulfides (1≤n≤4) deposited on the lithium surface, resulting in continuous fading of capacity and low utilization of active materials.

Fourth, during the charge and discharge process, the sulfur electrode will shrink and expand accordingly, which will destroy the physical structure of the electrode to a certain extent.

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