Electrolyte employing propylene carbonate as main solvent and lithium-ion battery

Abstract

The invention discloses an electrolyte employing propylene carbonate as a main solvent and a lithium-ion battery. The electrolyte is prepared from a lithium salt, an organic solvent and an additive, wherein the organic solvent comprises the propylene carbonate and other non-aqueous solvents; the propylene carbonate is 10%-60% of total mass of the electrolyte; the additive comprises a conventional film-forming additive and a novel functional additive AB or AXB; the content of the conventional film-forming additive in the electrolyte is 0.1%-10%; and the molar concentration of the functional additive is 0.001mol / L to 0.1mol / L, preferably 0.03mol / L to 0.06mol / L. According to the functional additive of the electrolyte, an electrolyte system can be prompted to form stable interfacial films on the surfaces of a cathode and an anode; a propylene carbonate solvent is effectively restrained from being embedded into a graphite layer along with lithium ions; and the initial efficiency, the cycle performance and the low-temperature discharge property of the battery are effectively improved.

Description

technical field [0001] The present invention relates to lithium ion battery electrolyte, particularly relate to a kind of lithium ion battery electrolyte that adopts propylene carbonate (PC) as the main solvent of electrolyte, in this electrolyte, add the additive that can suppress PC to embed graphite negative electrode, thereby can Significantly improve the first-time efficiency, cycle performance and low-temperature discharge performance of the battery. Background technique [0002] At present, graphite materials such as natural graphite are the most used in lithium-ion battery anode materials, and PC solvent cannot form an effective passivation film on the surface of these graphite electrodes, and it is easy to intercalate with lithium ions into the graphite layer, causing damage to the graphite electrode structure. Destruction leads to low reversible capacity of the battery, poor cycle performance, and seriously affects battery performance. Therefore, at present, a smal...

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Problems solved by technology

[0002] At present, graphite materials such as natural graphite are the most used in lithium-ion battery anode materials, and PC solvent cannot form an effective passivation film on the surface of these graphite electrodes, and it is easy to intercalate with lithium ions into the graphite layer, causing damage to the graphite electrode structure. Destruction, resulting in low reversible capacity of the battery, poor cycle performance, and seriously affecting battery performance. Therefore, at present, a small amount of PC is mainly added as an additive to improve the low-temperature performance of the electrolyte, and it cannot replace EC as the main component of the solvent.

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