Non-aqueous organic high-voltage electrolyte additive, non-aqueous organic high-voltage electrolyte and lithium ion secondary battery

Abstract

Embodiments of the invention provide a non-aqueous organic high-voltage electrolyte additive. The chemical structural formula of the additive is shown in a formula (1); and in the formula, i is 0 or 1, j is 0 or 1, and R1 and R2 are independently selected from the group consisting of oxygen, an alkyl group, a halogenated alkyl group, an alkyloxy group and a halogenated aromatic group. In the process of charging and discharging of a high-voltage lithium ion secondary battery, the non-aqueous organic high-voltage electrolyte additive can promote formation of a layer of a compact and stable SEI protection film on the surface of a positive electrode material, inhibit contact between an electrolyte and electrode active materials and reduce oxygenolysis of the electrolyte on the surfaces of electrodes, thereby improving cycle performance and discharge capacity of the lithium ion secondary battery under the condition of high voltage. Embodiments of the invention also provide a non-aqueous organic high-voltage electrolyte containing the non-aqueous organic high-voltage electrolyte additive and a lithium ion secondary battery.

Description

technical field [0001] The invention relates to the field of lithium-ion secondary batteries, in particular to a non-aqueous organic high-voltage electrolyte additive, a non-aqueous organic high-voltage electrolyte and a lithium-ion secondary battery. Background technique [0002] With the expansion of the application field of lithium-ion secondary batteries, including the introduction of new application scenarios such as large-scale energy storage power stations and base station power supply in recent years, people's demand for high-energy lithium-ion secondary batteries has become more urgent. [0003] In order to realize the high energy of lithium-ion secondary batteries, it is generally achieved by increasing the operating voltage of lithium-ion secondary batteries or developing high-energy cathode materials. The high-voltage cathode materials that have been reported include LiCoPO 4 、LiNiPO 4 , and LiNi 0.5 mn 1.5 o 4 etc., its charging voltage platform is close to...

AI Technical Summary

Problems solved by technology

The high-voltage cathode materials that have been reported include LiCoPO 4 、LiNiPO 4 , and LiNi 0.5 mn 1.5 o 4 etc., its charging voltage platform is close to or higher than 5V, but the matching non-aqueous organic electrolyte seriously lags behind the development of high-voltage cathode materials, which limits the application of lithium-ion secondary batteries

Conventional commercial electrolytes will oxidize and decompose on the surface of the positive electrode of the battery at a high potential above 4.5V. The oxidative decomposition reaction of the electrolyte itself will also promote malignant reactions such as changes in the morphology of the positive electrode material and structural collapse, which will eventually lead to lithium-ion secondary batteries. Decreased cycle performance, volume expansion, and decreased discharge capacity, so it cannot be applied to high-voltage lithium-ion secondary battery systems

e.g. 1M LiPF 6 A non-aqueous organic electrolyte dissolved in a carbonate solvent. In a high-voltage battery system above 4.5V, the non-aqueous organic electrolyte will have a side reaction with the positive electrode material during charging and then be oxidized and decomposed to generate CO 2 、H 2 Oxidation products such as O, CO 2 The generation of H will pose a potential threat to the safety performance of the battery; H 2 The generation of O makes the LiPF 6 / Carbonate electrolyte system undergoes autocatalytic reaction, and the generation of intermediate product HF will lead to LiMn 1.5 Ni 0.5 o 4 The dissolution of material metal atoms Mn and Ni causes the structure of the material to be distorted or collapsed

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