High-rate capacity power battery electrolyte

Abstract

The invention provides a high-rate capacity power battery electrode. The high-rate capacity power battery electrode comprises a lithium salt, a non-aqueous organic solvent, a functional additive and a film formation additive, wherein the film formation additive is lithium salt bi-fluoride phosphorous acid. On the basis of an existing functional additive such as an electrolyte containing VC, a new lithium salt additive LiDFP is added, the chemical constituent of a solid electrolyte interface (SEI) film is optimized, Li<+> transmission dynamics of a negative electrode / electrolyte interface is improved, and high-rate cycle property of a power battery is improved.

Description

[0001] 【Technical field】 [0002] The invention relates to the technical field of lithium batteries, in particular to an electrolyte solution for a high-rate capacity power battery. [0003] 【Background technique】 [0004] At present, lithium batteries have been more and more widely used in the field of electric vehicles. Although the existing commercial electrolyte negative electrode functional additives such as vinylene carbonate VC form a polymer SEI film (solid electrolyte interface, solid electrolyte interface film) with high film-forming efficiency and good cycle stability, the film-forming resistance is high, and the high-pressure negative electrode In reality, it further hinders the migration of lithium ions during the high-rate charging and discharging process of the battery, and cannot meet the requirements of high-rate and high-capacity power batteries. The improvement of the rate performance of the existing electrolyte can reduce the viscosity of the electrolyte th...

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Problems solved by technology

Publication No. CN1925207A patent adds crown ether to the electrolyte to improve the conductivity of the electrolyte to a certain extent, but the rate performance is still limited by the negative electrode / electrolyte interface ion conduction, and the crown ether is highly toxic and expensive, and is not suitable for large quantities. Application; CN 102496739A patent reduces the viscosity of the electrolyte and the dissociation degree of the lithium salt through the introduction of the fluorine-containing solvent FEC, improves the ionic conductivity of the electrolyte and the diffusion rate of ions in the electrode material, and effectively reduces the SEI membrane impedance, but the FEC Too much is easy to produce HF on the surface of the negative electrode, causing adverse side reactions; the same CN103715457A patent uses dimethylacetamide as an additive, which only improves the conductivity of the non-aqueous electrolyte, and cannot fundamentally meet the high-rate and high-capacity requirements of the battery. Require

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