Semi-solid lithium-sulfur battery and preparation method thereof

Abstract

The invention discloses a semi-solid lithium-sulfur battery and a preparation method thereof. The semi-solid lithium-sulfur battery comprises a sulfur-carbon positive electrode, a composite solid-state negative electrode, an electrolyte, a diaphragm and a shell, and the composite solid-state negative electrode comprises a current collection layer, a negative electrode active material, electronic conductive particles, a binder and a continuous solid electrolyte layer, and the solid electrolyte layer uniformly and compactly coats the surfaces of the negative electrode active material and the electronic conductive particles and / or the interiors of pores contained in the negative electrode active material and the electronic conductive particles, so that a continuous electronic transmission channel is formed, and the negative electrode active material is not in contact with the electrolyte. According to the semi-solid lithium-sulfur battery disclosed by the invention, the sulfur-carbon positive electrode, the negative electrode material with the surface modification layer and the liquid electrolyte are adopted to assemble the battery, and the liquid electrolyte is completely separated from the electrode, so that side reaction generated between the electrolyte and the electrode in an electrochemical process can be completely blocked; and the influence of the room-temperature ionic conductivity of the solid electrolyte on the battery can be reduced, and the safety performance and the long cycle performance of the battery are effectively improved.

Description

technical field [0001] The invention relates to a semi-solid battery, in particular to a novel semi-solid lithium-sulfur battery and a preparation method thereof, belonging to the technical field of solid-state lithium batteries. Background technique [0002] With the rapid development of mobile electronic devices and power batteries, the requirements for the energy density of energy storage battery systems are constantly increasing, and traditional lithium-ion batteries have become more and more difficult to meet the corresponding requirements. In addition, it is imminent to develop secondary batteries that have good safety, economy, and environmental friendliness at the same time. The lithium-sulfur battery system not only has good safety performance, but also has a very high energy density. The energy density of the positive active material sulfur (S8) reaches 1675 mAh / g, and the active material is cheap and environmentally friendly. However, the use of lithium-sulfur b...

AI Technical Summary

Problems solved by technology

The main disadvantage of these technologies is that although the solid electrolyte is introduced to replace the liquid electrolyte to improve the safety performance and cycle performance of the battery, the electrolyte is still in contact with the negative electrode, which cannot prevent the electrolyte and dissolved polysulfides from contacting the negative electrode. At the same time, if the electrolyte itself is changed to a solvent with poor solubility of lithium sulfide, or a solid / semi-solid electrolyte, due to the reduced solubility of the positive electrode product lithium sulfide, it will lead to The capacity of the active material is also greatly affected

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