EC-free lithium ion battery electrolyte and application thereof

Abstract

The invention provides an EC-free lithium ion battery electrolyte and application thereof. The EC-free lithium ion battery electrolyte comprises an electrolyte lithium salt, an organic solvent and an additive, wherein the additive comprises a positive electrode additive and a negative electrode additive, and the positive electrode additive comprises 1-propylene-1,3-sultone. According to the EC-free lithium ion battery electrolyte, an EC-free solvent and 1-propylene-1,3-sultone cooperate with each other, so that the cycling stability of the battery at high voltage (4.4 V) is effectively improved, and thus, the stability of high temperature and cycle performance of the battery under high voltage is effectively improved.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries, and relates to an EC-free lithium ion battery electrolyte and an application thereof. Background technique [0002] With the wide application of consumer electronics and new energy vehicles, high specific energy lithium-ion batteries have become one of the research hotspots of researchers, and the specific capacity of materials and the upper limit voltage of charging directly determine the energy density of batteries. The charging upper limit voltage depends on the stability of the positive electrode material and electrolyte under high voltage. In order to meet the demand for high energy density of lithium-ion batteries, the high nickel-silicon carbon system is currently considered to be one of the most promising battery systems, and the matching electrolyte technology plays a vital role. After years of development and continuous optimization, the current commercial power battery electrolyte...

AI Technical Summary

Problems solved by technology

This application uses cetyltrimethylammonium, butyltrimethylammonium and lithium bisoxalate borate to replace the traditional LiPF6 as the electrolyte. The electrolyte is completely composed of anions and cations at room temperature Liquid organic salt, with electrical conductivity, higher decomposition voltage than conventional electrolyte, non-volatile and non-flammable in a wide temperature range; the electrolyte has high conductivity and good mechanical properties, because there is no solvent volatilization and leakage, etc. phenomenon, which can improve the safety and stability of the battery; after testing, the lithium-ion polymer battery using the electrolyte of this application can meet the requirements of 5C fast charging, but the melting point of ethylene carbonate (EC) used in it is 36.5 ° C, It is solid at normal temperature, and it is easy to crystallize and precipitate at low temperature, the viscosity increases, and the electrical conductivity decreases, resulting in poor low temperature electrical properties

[0005]The above schemes all use ethylene carbonate as a solvent, which will lead to poor safety performance under high pressure and poor point performance at low temperature. However, an electrolyte that can ensure conductivity and cycle performance is very necessary