A kind of electrolyte used in lithium, sodium and potassium batteries

Abstract

The invention provides an electrolyte additive, an electrolyte and an application of the electrolyte, belonging to the technical field of lithium metal batteries, and the specific technical scheme is as follows: an electrolyte additive, the additive is an organic compound salt containing phosphorus and boron, Its cation part is a phosphorus-containing cation with four benzene rings, and its anion part is a boron-containing anion with four benzene rings. The additive is used in the electrolyte, and the effect of inhibiting dendrites is outstanding, which can improve the lithium metal. (or sodium or potassium) cycle performance and safety performance of the battery, while ensuring that it brings into play the high energy density advantage of the metal lithium (or sodium or potassium) negative electrode; the general structural formula of the additive is as follows:

Description

technical field [0001] The invention belongs to the technical field of lithium batteries, in particular to an electrolyte used in lithium, sodium and potassium batteries. Background technique [0002] The theoretical specific capacity of metallic lithium is as high as 3860 mAh / g and the electrode potential is as low as -3.04V (compared to standard hydrogen electrodes). Using it as a negative electrode can significantly increase the energy density of lithium batteries. However, lithium dendrites are likely to be generated due to uneven deposition during the use of lithium metal negative electrodes. On the one hand, lithium dendrites will penetrate the battery separator and cause short circuits and induce battery safety problems; on the other hand, they will intensify the side reactions between lithium metal and electrolyte and Generation of dead lithium leads to deterioration of cycle performance. There are many methods to solve the uneven deposition of lithium metal, one of...

AI Technical Summary

Problems solved by technology

[0004] Although a wide variety of lithium metal battery electrolyte additives have been developed, and these additives can also inhibit the generation of lithium dendrites to a certain extent, the inhibitory ability of these additives to lithium dendrites is not enough to make lithium metal negative electrodes truly It has been widely used in commercial batteries, and the ability of additives to inhibit lithium dendrites still needs to be further improved. It is of great significance to develop new additives with better inhibitory effects on lithium dendrites for lithium metal battery electrolytes

In addition, even for battery systems with non-metallic negative electrodes, such as lithium-ion batteries that have been commercially used on a large scale, and sodium-ion batteries and potassium-ion batteries that are still under research, such battery systems with non-metallic negative electrodes are under normal conditions. Metal dendrites will not be generated on the negative electrode, but there is still a high risk of dendrite precipitation under extreme conditions such as fast charging, low temperature charging, and long-term cycling.

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