High-voltage-resistant low-temperature lithium ion electrolyte

Abstract

The invention discloses a high-voltage-resistant low-temperature lithium ion electrolyte, and belongs to the technical field of electrochemical energy storage. The lithium ion electrolyte comprises a main solvent, a diluent, a film-forming additive and a lithium salt, the main solvent accounts for 20-40% of the total mass of the electrolyte, the diluent accounts for 40-65% of the total mass of the electrolyte, the film-forming additive accounts for 5-15% of the total mass of the electrolyte, and the lithium salt accounts for 8-15% of the total mass of the electrolyte. The lithium ion electrolyte, the main solvent and the diluent act on the solvation structure of the lithium ion, so that the lithium ion has small desolvation energy, and when the lithium ion electrolyte is applied to the lithium ion battery, the lithium ion battery can show excellent low-temperature discharge performance and low-temperature cycle performance.

Description

technical field [0001] The invention belongs to the technical field of electrochemical energy storage, and in particular relates to a high-voltage-resistant low-temperature lithium-ion electrolyte. Background technique [0002] With the increasing demand for energy in the fields of electronics, power, and military industry, the energy density of lithium batteries is required to increase accordingly. One of the feasible ways to increase the energy density of lithium-ion batteries is to use high-voltage cathode materials with a high operating voltage platform, such as LiNi x co 1-x PO 4 (4.8~5.1V vs. Li / Li + ), Li 2 CoPO 4 F(5.1V vs. Li / Li + ), LiNi 0.5 mn 1.5 o 4 (4.7V vs. Li / Li + )Wait. The electrochemical window of the general carbonate electrolyte is below 4.5V. Forcibly applying it to a high-voltage battery will cause the electrolyte to oxidize and decompose at a high potential, resulting in an increase in the irreversible capacity of the battery, which in turn...

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Problems solved by technology

[0004] The current prior art, such as CN 111430799, CN 110504489, etc., is mainly aimed at improving the cycle performance of high-voltage lithium-nickel-manganese-oxide batteries at normal temperature or high temperature, and there is no research and development on improving the low-temperature performance of high-voltage lithium-ion batteries. According to reports, this is seriously inconsistent with the actual use of lithium-ion batteries in deep-sea operations, polar exploration, etc. Therefore, it is of great practical significance to study high-voltage-resistant low-temperature lithium-ion electrolytes

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