High and low temperature performance-considered high-voltage electrolyte and lithium ion battery thereof

[0030] Example 1

[0031] 1) Preparation of electrolyte

[0032] Mix ethylene carbonate (EC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC) according to the mass ratio EC:EMC:DEC=1:1:1, and then add lithium hexafluorophosphate (LiPF 6 ) To a molar concentration of 1 mol / L, and then add 1% of ethylene cyclic tricarbonate based on the total mass of the electrolyte.

[0033] 2) Preparation of positive plate

[0034] Mix positive electrode active material LiCoO in a mass ratio of 93:4:3 2 Doped LiNi 0.5 Co 0.2 Mn 0.3 O 2 Mixed materials (where the mass is higher than LiCoO 2 :LiNi 0.5 Co 0.2 Mn 0.3 O 2 =1:1), conductive carbon black Super-P and binder polyvinylidene fluoride (PVDF), and then disperse them in N-methyl-2-pyrrolidone (NMP) to obtain positive electrode slurry. The slurry is evenly coated on both sides of the aluminum foil, dried, calendered and vacuum dried, and then the aluminum lead wires are welded with an ultrasonic welder to obtain a positive electrode plate wi

[0056] Example 2

[0057] Except that the preparation of the electrolyte reduces the additive amount of cyclic ethylene tricarbonate from 1% to 0.1%, the others are the same as in Example 1. The tested room temperature cycle performance, high temperature cycle performance, high temperature storage performance and low temperature storage performance are shown in the table 1 shown.

[0058] Example 3

[0059] Except that the preparation of the electrolyte increases the additive amount of cyclic tricarbonate from 1% to 2%, the others are the same as in Example 1. The tested room temperature cycle performance, high temperature cycle performance, high temperature storage performance and low temperature storage performance are shown in the table 1 shown.