Electrolyte for lithium ion battery using silica-based material as negative electrode material and lithium ion battery

Abstract

The invention discloses an electrolyte for a lithium ion battery using a silica-based material as a negative electrode material and the lithium ion battery. The electrolyte comprises a lithium salt, a non-aqueous organic solvent and a film formation additive, wherein the non-aqueous organic solvent comprises ethylene carbonate; the film formation additive comprises TPFPB Tris(pentafluorophenyl) borane. The TPFPB in the electrolyte is used as the film formation additive of an SEI film, can facilitate the formation of the stable and integral SEI film on the surface of the negative electrode material, and can weaken an efflorescence phenomenon caused by a silicon volume effect when the silica-based material is used as the negative electrode material; the TPFPB can release freely moving lithium ions through the SEI film, so that part of lithium ions consumed during the formation process of the SEI film can be offset, lithium ion consumption can be lowered, and the charging and discharging efficiency and the cycle performance can be improved. The structural characteristic of the TPFPB determines that the TPFPB is relatively stable and not easy to decompose, so that the service life of the electrolyte is prolonged.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to an electrolyte solution for lithium ion batteries and a lithium ion battery using silicon-based materials as negative electrode materials. Background technique [0002] Lithium-ion batteries have attracted people's attention because of their advantages such as high energy density and good cycle performance, and have been developed rapidly in the past two decades. Electric vehicles are mainly powered by lithium-ion batteries. With the gradual development of electric vehicles, people have put forward higher requirements for the energy density of lithium-ion batteries. The current commercial lithium-ion battery anode material uses graphite anode material, which has a low charge-discharge specific capacity and a theoretical capacity of 372mAh / g. wide range of needs. [0003] Silicon-based materials have become one of the most ideal candidate materials to r...

AI Technical Summary

Problems solved by technology

However, existing LiB(C 2 o 4 ) 2 (Lithium oxalate borate) system electrolyte, LiPF 6 (Lithium hexafluorophosphate) system electrolyte, due to its poor conductivity or the inability to form a dense SEI film on the surface of silicon-based materials, thus resulting in low charge and discharge efficiency and poor cycle performance of lithium-ion batteries using silicon-based materials as negative electrode materials. Some lithium-ion battery electrolytes that use silicon-based materials as negative electrode materials are difficult to adapt to practical applications

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