Matched silicon-carbon anode lithium-ion battery electrolyte and silicon-carbon anode lithium-ion battery

Abstract

The invention relates to the technical field of the lithium-ion batteries, and in particular relates to a matched silicon-carbon anode lithium-ion battery electrolyte and a silicon-carbon anode lithium-ion battery. The lithium-ion battery electrolyte is composed of a non-aqueous organic solvent, a lithium salt and additives, wherein the additives comprise fluoroethylene carbonate, ethylene sulfite and a borate compound with a M type structure. Compared with the prior art, a SEI film formed on the surface of the electrode is more stable and compact through the synergistic effect produced by the combination use of more than three additives, the physical structure stability and chemical structure stability of the silicon-carbon anode surface are improved, so that the battery has good circulation performance and high-temperature storage performance, and meanwhile, the battery gas production is restrained.

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular to a matching silicon-carbon negative-electrode lithium-ion battery electrolyte and a silicon-carbon negative-electrode lithium-ion battery. Background technique [0002] With the rapid increase in the types and quantities of digital products, new energy vehicles will show a massive growth in the next few years. According to the "Energy Saving and New Energy Vehicle Industry Development Plan", the power battery requires an energy density of 300Wh / Kg by 2020. Development A battery system with high energy density is imperative. The energy density of the negative electrode material is particularly constrained to the battery system. The theoretical gram capacity of the commonly used graphite negative electrode is 372mAh / g, and the products developed in the industry are close to this theoretical value. The theoretical gram capacity of silicon anode can reach 4200mAh / g, whi...

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Problems solved by technology

[0005] The research on the electrolyte of the silicon negative electrode in the above-mentioned literature is mainly based on the half-cell. Although the use of additives in the above-mentioned patents has a certain effect on the improvement of the electrical performance of the silicon negative electrode battery, the performance of the improved battery is still poor, especially The long-life cycle performance of the battery is poor, the volume expansion is obvious and the internal resistance changes greatly, and the battery is easy to produce gas under high temperature storage conditions

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