High Voltage Electrolyte for Li-ion Batteries

Abstract

The invention discloses high-voltage electrolyte for a lithium ion battery. The high-voltage electrolyte comprises high-voltage-resistance 5V electrolyte for the lithium ion battery, and comprises fluoro carbonate compounds, fluorinated ether compounds, lithium oxalyldifluroborate and lithium hexafluorophosphate, wherein 100 parts by weight of a solvent of the electrolyte, the electrolyte comprises, 30-70 parts by weight of the fluoro carbonate compounds, 30-70 parts by weight of the fluorinated ether compounds, 1-5 parts by weight of lithium oxalyldifluroborate; the mole concentration of electrolyte lithium salt which does not contain lithium oxalyldifluroborate in the solvent is 0.9-1.5mol / L. The invention provides the multifunctional lithium ion battery electrolyte with the self-extinguish time less than 5 seconds, the viscosity less than 2cp and high voltage stability, and the multifunctional lithium ion battery electrolyte is applied to commercial positive electrode materials, such as lithium nickel manganese oxide, lithium cobalt phosphate, lithium vanadium phosphate, high-voltage nickel cobalt manganese ternary materials, lithium ferric manganese phosphate, and high-voltage lithium cobalt oxide, and negative electrode materials, such as graphite and lithium titanate.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, in particular to an electrolyte solution for lithium ion batteries. Background technique [0002] Energy density, low cost and safety are the main directions of research in the lithium-ion battery industry. The energy of a lithium-ion battery is determined by the capacity of the lithium battery and the cut-off voltage of the charge. Therefore, in order to increase the energy density of the lithium battery, it is necessary to increase the cut-off voltage of the charge or adopt a new high-energy-density lithium battery material system. Although the development of most new high-energy-density lithium battery materials, such as lithium-rich manganese-based cathode materials, has become a research and development hotspot worldwide, it is still in the basic research stage. Therefore, increasing the charging cut-off voltage has become a hot spot in current research and development. The discharge v...

AI Technical Summary

Problems solved by technology

For fluorine-containing ethers, the boiling point is relatively low, so it is difficult to use alone

There is also low compatibility with carbonate used as a solvent for electrolyte salt dissolution, which easily causes two-phase separation, and it is not easy to form a stable Solid Electrolyte Interface (SEI) film

[0005]Because of the above reasons, the currently published patents mainly use the mixture of fluorinated solvent and conventional solvent as high-voltage electrolyte, but in fact, once the fluorinated solvent is mixed with conventional electrolytic After the liquid is mixed, the oxidation resistance of the mixed electrolyte is reduced

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