Nitrile electrolyte for lithium metal battery and lithium metal battery using the same

Abstract

The invention discloses a nitrile electrolyte for a lithium metal battery and a lithium metal battery using the same, and the nitrile electrolyte is composed of at least two lithium salts and at leastone solid or liquid reagent containing cyano functional groups. For the nitrile electrolyte for the lithium metal battery provided by the invention, the ionic conductivity at the room temperature canreach a level equivalent to that of a traditional carbonic ester electrolyte and can reach 10<-2>S cm<-2>. The battery assembled by using the electrolyte with a lithium metal negative electrode as the soft package still has a capacity retention rate of about 95% after 30 turns of large-surface capacity (4mA h cm<-2>) circulation, compared with the capacity retention rate (55%) of the soft packageassembled by the traditional carbonic ester electrolyte, the capacity retention rate is much larger. Moreover, the half-cell of lithium cobalt oxide / lithium is cycled at a multiplying power of 1C under a high voltage of 3-4.7 V, and the capacity retention rate of 74% after 500 cycles can be still achieved. The nitrile electrolyte for the lithium metal battery can effectively inhibit expansion ofthe soft package battery.

Description

technical field [0001] The invention relates to a room temperature ionic liquid electrolyte, in particular to a non-carbonate, room temperature double-salt ion nitrile electrolyte system suitable for lithium metal batteries. Background technique [0002] As an important part of lithium metal batteries, electrolyte has a very important impact on the performance of lithium metal batteries. The use of room temperature ionic liquids to replace traditional carbonate-based liquid electrolytes can effectively reduce the problems of flammability, explosion and severe flatulence of lithium metal batteries. At the same time, room temperature ionic liquids can also achieve ionic conductivity and electrochemical stability window comparable to traditional carbonate electrolytes. The introduction of the double salt stabilizes the interface between the electrolyte and lithium metal to a large extent on the one hand, and on the other hand greatly improves the ion transport capacity of the ...

AI Technical Summary

Problems solved by technology

However, an effective SEI film cannot be formed between the nitrile electrolyte and the lithium metal anode.

Therefore, nitrile materials cannot be used as the main solvent of the electrolyte

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