Lithium ion battery non-aqueous electrolyte and lithium ion battery

Abstract

The invention provides a lithium ion battery non-aqueous electrolyte and a lithium ion battery. The lithium ion battery non-aqueous electrolyte comprises an electrolyte, a non-aqueous solvent and an additive, wherein the additive comprises a sulfonate additive and an ether compound. The invention provides the lithium ion battery non-aqueous electrolyte which is prepared by compounding the sulfonate additive and the ether compound additive so that side reaction, stress corrosion cracking, transition metal dissolution and impedance increase between a positive electrode material and the electrolyte can be inhibited; and the non-aqueous electrolyte of the lithium ion battery can also avoid the problem of lithium metal pulverization in the lithium supplement process of a silicon-carbon negative electrode, then the highly reversible circulation of lithium metal is realized, the stable circulation of the lithium ion battery is realized, and the reversible specific capacity of a ternary positive electrode material and the first coulombic efficiency of a silicon negative electrode material are remarkably improved.

Description

technical field [0001] The invention belongs to the field of batteries, and in particular relates to a non-aqueous electrolyte solution of a lithium ion battery and a lithium ion battery. Background technique [0002] Lithium-ion batteries with high energy density are currently in demand for portable electronic devices, drones, and electric vehicles. The mass energy density of Li-ion batteries based on graphite anodes can reach about 280 Wh / kg. In order to further increase the mass energy density of the battery to more than 350-400Wh / kg, most lithium-ion batteries use silicon-oxygen or silicon-carbon as the negative electrode material and high-nickel ternary positive electrode material (LiNi 0.8 mn 0.1 co 0.1 ) as the cathode material. [0003] As a material with high element abundance in nature, silicon has a specific capacity as high as 3590mgA / g, so it is expected to replace the carbon anode material widely used in commercial lithium-ion batteries. However, on the on...

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Problems solved by technology

However, on the one hand, during the lithiation / delithiation process, the silicon negative electrode is prone to volume expansion / collapse, resulting in an extremely unstable SEI film formed between the negative electrode material and the electrolyte. With ester additives, a stable SEI film cannot be formed on the surface of the silicon negative electrode

On the other hand, silicon oxide (SiO X ) as a negative electrode material also has a high specific capacity, but the bond energy of the Si-O bond is twice that of the Si-Si bond, and SiOx will generate a lithium-oxygen compound (Li X O), and then lead to the first Coulombic efficiency of the silicon oxide material is only about 70%, and the first efficiency is only increased to about 80% at present, which still has a large gap with the first Coulombic efficiency of the graphite material (94%)

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