High-voltage ternary lithium ion battery electrolyte and high-voltage ternary lithium ion battery

Abstract

The invention belongs to the technical field of lithium ion batteries, and relates to a high-voltage ternary lithium ion battery electrolyte. The high-voltage ternary lithium ion battery electrolyte comprises a lithium salt, a non-aqueous organic solvent and an additive, and the additive contains vinylene carbonate, 1, 3-propane sultone and fluoroethylene carbonate and also comprises a combinationof a phosphate compound A, a sulfonate compound B and a sulphurous acid compound C. Compared with the prior art, through the synergistic effect of the compounds A, B and C, the electrolyte disclosedby the invention not only can improve the high-temperature performance of the lithium ion battery under high voltage, but also greatly improves the cycle performance and low-temperature performance ofthe battery. In addition, the invention also provides a high-voltage ternary lithium ion battery using the electrolyte.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a high-voltage ternary lithium-ion battery electrolyte and a high-voltage ternary lithium-ion battery. Background technique [0002] With the continuous improvement of the energy density requirements of lithium-ion batteries, the charging cut-off voltage of ternary lithium-ion batteries is also increasing. At present, the high-voltage ternary lithium-ion batteries of 4.35V and above and the ternary lithium-ion batteries below 4.35V on the market Compared with the ubiquitous problems such as reduced high-temperature storage performance at full charge, fast attenuation of high-temperature cycle life, and low-temperature discharge lithium deposition, etc. [0003] The charge cut-off voltage of the ternary battery is increased from 4.35V to 4.40V and above, and its energy density is significantly improved. But at the same time, the performance of the batter...

AI Technical Summary

Problems solved by technology

On the one hand, at high temperature, the LiPF in the electrolyte 6 It is extremely easy to decompose and produce HF to corrode the positive electrode active material, resulting in the dissolution of metal ions; on the other hand, under high voltage, the transition metal oxide of the positive electrode active material is easily reduced and dissolved, and the transition metal ion passes through the SEI film on the surface of the negative electrode. It is reduced to metal simple substance, which leads to the continuous increase of the negative electrode impedance and deteriorates the performance of the battery

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