Electrolyte and lithium ion battery comprising same

Abstract

The invention provides an electrolyte and a lithium ion battery comprising the same. The electrolyte adopted by the invention comprises a non-aqueous organic solvent, an electrolyte lithium salt and an electrolyte functional additive, wherein the electrolyte functional additive contains a polynitrile compound and a bis (trimethylsilyl) nitrogen-containing heterocyclic compound. The inventor creatively discovers that a Si-N bond in the bis (trimethylsilyl) nitrogen-containing heterocyclic compound has higher electronegativity compared with a C-N bond in a polynitrile compound, and can be preferentially combined with a proton H < + > generated by oxygenolysis of electrolyte components, so that weakening of the complexing ability of the proton H < + > on the polynitrile compound is avoided, and the stability of the electrolyte is improved. Compared with a single multi-nitrile compound, the synergism of the two can better stabilize the interface property of a positive electrode / electrolyte, and inhibit the dissolution of transition metal ions and the further oxygenolysis of electrolyte components, so that the lithium ion battery applying the electrolyte system has excellent long cycle stability.

Description

technical field [0001] The invention belongs to the technical field of lithium ion battery materials, and in particular relates to an electrolyte and a lithium ion battery including the electrolyte. Background technique [0002] In recent years, with the rapid development of portable smart electronic products, lithium-ion batteries, which play an important role in them, have become the focus of attention; the development of lithium-ion batteries is directly related to the development of smart electronic products to a certain extent: Among them, The high battery life of smart electronic products is the focus of consumers' attention, and this is inseparable from the energy density of lithium-ion batteries. [0003] Improving the energy density of lithium-ion batteries has always been an important topic in the industry. One of the important means to increase energy density is to increase the charge cut-off voltage of the battery, but the problems caused by increasing the charg...

AI Technical Summary

Problems solved by technology

However, after the battery has experienced long-term cycling, the complexation ability of polynitrile compounds to transition metal ions will suffer significant deterioration, and the later stage will appear in a "weak" state.

In addition, the stability of the positive extreme interface is insufficient, causing the battery to show a "weak" state during long-term cycling, which cannot guarantee the later performance

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