Non-aqueous electrolyte and secondary lithium battery

Abstract

The invention relates to a non-aqueous electrolyte. The electrolyte comprises lithium salt, an organic solvent and a functional additive, the functional additive comprises a triphenylphosphine derivative, and the structural general formula of the triphenylphosphine derivative is shown in the specification, wherein R1, R2 and R3 are independently selected from hydrogen, hydroxyl, halogen, alkyl, alkoxy, halogenated alkyl, halogenated alkoxy, alkenyl, halogenated alkenyl, phenyl, halogenated phenyl, biphenyl, halogenated biphenyl, phenyl ether, triphenyl, halogenated phenyl ether, halogenated triphenyl, amino, ester or cyano, the halogen is F, Cl or Br, and the halogenation is partial substitution or complete substitution. The electrolyte disclosed by the invention can well inhibit the dissolution of metal ions in the positive electrode material, protect the positive electrodes, effectively reduce the thickness expansion of the lithium battery and improve the capacity retention ratio ofthe secondary lithium battery.

Description

technical field [0001] The invention belongs to the technical field of materials, and in particular relates to a nonaqueous electrolyte and a secondary lithium battery. Background technique [0002] With the rapid development of portable electronic devices, hybrid vehicles, electric vehicles, and space technology, secondary batteries have put forward higher requirements in terms of specific capacity, cycle life, and safety. Lithium-ion battery cathode materials currently widely used are lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, and the like. And as the battery charge-discharge cycle proceeds, the metal ions in the positive electrode material are dissolved into the electrolyte, and the reaction between the positive electrode active material and the electrolyte is also accelerated, resulting in serious gas swelling of the battery during the cycle, and the battery capacity decays significantly. The performance is reduced, which seriously restricts ...

AI Technical Summary

Problems solved by technology

And as the battery charge-discharge cycle proceeds, the metal ions in the positive electrode material are dissolved into the electrolyte, and the reaction between the positive electrode active material and the electrolyte is also accelerated, resulting in serious gas swelling of the battery during the cycle, and the battery capacity decays significantly. The performance is reduced, which seriously restricts the performance of the positive electrode material

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