Additive and electrolyte and lithium ion battery using same

Abstract

The invention discloses an additive and an electrolyte and a lithium ion battery using the additive, the additive comprises a compound 1, a compound 2 or a compound 3, the additive can orderly form a film when the battery is charged and discharged for the first time, and a formed solid electrolyte interface film has the characteristics of strong conductivity, strong ionic conductivity and low electron conductivity; therefore, the rate cycle performance, the rate discharge performance and the storage performance of the lithium ion battery can be effectively improved.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to an additive, an electrolyte using the additive, and a lithium ion battery. Background technique [0002] Due to the advantages of high power density and energy density, small size, and long life, lithium-ion batteries are widely used in consumer electronics, mobile terminals, communication energy storage, and electric vehicles. However, in recent years, as consumers have higher and higher charging and discharging requirements for electronic products and electric vehicles, the problems of long charging time and low rapid discharge capacity of lithium-ion batteries have been plaguing the lithium-ion battery market. The rate of deintercalation and intercalation of lithium-ion batteries in the positive / negative active material, that is, the speed at which lithium ions run out of the positive / negative active material, or the speed at which they enter the acti...

AI Technical Summary

Problems solved by technology

However, in recent years, as consumers have higher and higher charging and discharging requirements for electronic products and electric vehicles, the problems of long charging time and low rapid discharge capacity of lithium-ion batteries have been plaguing the lithium-ion battery market.

The rate of deintercalation and intercalation of lithium-ion batteries in the positive / negative active material, that is, the speed at which lithium ions run out of the positive / negative active material, or the speed at which they enter the active material from the surface of the positive / negative electrode to find a place to settle down How fast it is is an important factor affecting the charge and discharge rate; at the same time, the stability of the solid electrolyte interface film is also subject to a greater test. If the solid electrolyte interface film has many pores but the stability is not good, there is no Significance, so this also poses a great challenge to the solid electrolyte interface film on the positive and negative electrodes

[0003] In order to improve the ionic conductivity and interface stability of the solid electrolyte interface film of the positive electrode, a lot of related research has been done in the industry in recent years. The invention patent CN111162318A reports a lithium-ion battery electrolyte containing a thiophene conjoined compound, a thiophene conjoined compound With a lower oxidation potential, it can be better than the electrolyte solvent to form a CEI film on the surface of the positive electrode. Multiple thienyl groups in the conjoined structure are connected to each other to form a stable spatial structure, and the formed CEI film is denser and more stable; but not It is mentioned that the dense and stable CEI film formed by thiophene compounds will increase the self-discharge of lithium-ion batteries, which is not conducive to the storage performance of lithium-ion batteries

The invention patent CN113061102A mentions that the lithium battery additive contains a sulfonate compound with a sulfonamide structure, and its chemical stability is significantly improved compared with ordinary sulfonate compounds, so it can be stored for a long time at room temperature The electrolyte secondary energy storage device is more likely to decompose during the charge-discharge cycle of the secondary energy storage device and form an SEI film on the surface of the pole piece. The decomposition products contain a large amount of heteroatoms such as sulfur, nitrogen, and oxygen, and lithium ions are more likely to pass through the SEI film, thereby Improve the cycle performance of lithium-ion batteries; but it is not mentioned that the SEI film formed by sulfonamide is easily damaged at high rates and cannot be applied to high-rate batteries

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