A silicon-containing high-energy-density lithium-ion battery

Abstract

The invention relates to a silicon-containing high-energy-density lithium-ion battery, including a positive electrode, a silicon-containing negative electrode, a fluorine-containing electrolyte, a separator, tabs and packaging materials; the silicon-containing negative electrode uses silicon-based materials as all or part of the battery. Chemically active substances; the electrolyte contains lithium salts, non-aqueous organic solvents that can dissolve lithium salts, SEI film-forming additives, and hydrofluoroether; the solubility of lithium salts in the non-aqueous organic solvents that can dissolve lithium salts is high 2mol / L; the solubility of lithium salt in the hydrofluoroether is lower than 0.3mol / L; the non-aqueous organic solvent soluble in lithium salt is miscible with hydrofluoroether; the solubility of lithium salt in The non-aqueous organic solvent is miscible with the liquid SEI film-forming additive, and can dissolve the solid SEI film-forming additive. The silicon-containing lithium-ion battery has the advantages of high energy density, long cycle life, good rate characteristics, high safety performance, and is not easy to expand and deform.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, in particular to a high energy density lithium ion battery containing silicon. Background technique [0002] Due to the rapid development and wide application of various portable electronic devices, new energy electric vehicles and energy storage systems in recent years, there is an increasingly urgent need for lithium-ion batteries with high energy density, long cycle life, safe use, and good rate characteristics. [0003] At present, the anode material of commercial lithium-ion batteries is mainly graphite, but due to the low theoretical capacity (372mAh / g), the improvement of energy density of lithium-ion batteries is limited. Silicon-based anode materials have the advantage of high capacity that other anode materials cannot match. There are three main types of silicon-based anode materials, one is a composite material composed of elemental silicon or the same carbon; the other is a compo...

AI Technical Summary

Problems solved by technology

However, if the proportion of lithium salt in the electrolyte is too high, the viscosity of the electrolyte will be significantly increased, the activity of lithium ions will be reduced, and the mobility of lithium ions in the electrolyte will be significantly reduced. Wet, the result is that the actual capacity of the battery is low and the rate characteristics are poor.

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