KR-20260065536-A - NON-AQUEOUS ELECTROLYTE FOR SECONDARY BATTERY AND SECONDARY BATTERY COMPRISING THE SAME

Abstract

The present invention relates to a non-aqueous electrolyte and a lithium secondary battery comprising the same. The non-aqueous electrolyte of the present invention comprises a lithium salt, a non-aqueous electrolyte, and an additive, wherein the additive may comprise a compound represented by the following chemical formula 1. [Chemical Formula 1] (In the above chemical formula 1, R1 and R2 are each independently hydrogen or an alkyl group having 1 to 5 carbon atoms).

Inventors

• 지수현
• 이철행
• 이정민

Assignees

• 주식회사 엘지에너지솔루션

Dates

Publication Date

20260508

Application Date

20251027

Priority Date

20241101

Claims (10)

1. Lithium salt; comprising a non-aqueous organic solvent and additives, The above additive is a non-aqueous electrolyte comprising a compound represented by the following chemical formula 1: [Chemical Formula 1] (In the above chemical formula 1, R1 and R2 are each independently hydrogen or an alkyl group having 1 to 5 carbon atoms).
2. In paragraph 1, A non-aqueous electrolyte in which, in the above chemical formula 1, R1 and R2 are each independently hydrogen or an alkyl group having 1 to 3 carbon atoms.
3. In paragraph 1, A non-aqueous electrolyte in which the compound represented by Chemical Formula 1 above is at least one selected from the group consisting of compounds represented by Chemical Formulas 1A to 1D below: [Chemical Formula 1A] [Chemical Formula 1B] [Chemical Formula 1C] [Chemical Formula 1D] .
4. In paragraph 1, A non-aqueous electrolyte in which the compound represented by the above chemical formula 1 is included in an amount of 0.01% to 13.0% by weight based on the total weight of the non-aqueous electrolyte.
5. In paragraph 1, A non-aqueous electrolyte in which the compound represented by the above chemical formula 1 is included in an amount of 0.01% to 5.0% by weight based on the total weight of the non-aqueous electrolyte.
6. In paragraph 1, The above additive is a non-aqueous electrolyte that further comprises a lithium salt-based compound.
7. In paragraph 6, The above lithium salt-based compound is a non-aqueous electrolyte selected from the group consisting of lithium bis-oxalatoborate (LiB( C₂O₄ ) ₂ , LiBOB), lithium difluoro( oxalato )borate (LiDFOB), lithium difluorophosphate ( LiPO₂F₂ , LiDFP), and lithium difluoro(bis-oxalato)phosphate (LiDFOP).
8. In paragraph 6, The above lithium salt-based compound is included in an amount of 0.01% to 10.0% by weight based on the total weight of the non-aqueous electrolyte.
9. In paragraph 1, The above-mentioned non-aqueous electrolyte further comprises at least one auxiliary additive selected from the group consisting of cyclic carbonate compounds, halogen-substituted carbonate compounds, sulfone compounds, sulfate compounds, phosphate compounds, borate compounds, nitrile compounds, benzene compounds, amine compounds, and silane compounds.
10. anode; A cathode opposite to the anode above; A separator interposed between the above cathode and the above anode; and A lithium secondary battery comprising a non-aqueous electrolyte according to claim 1.

Description

Non-aqueous electrolyte and lithium secondary battery comprising the same The present invention relates to a non-aqueous electrolyte and a lithium secondary battery containing the same. As dependence on electrical energy gradually increases in modern society, the development of large-capacity power storage devices capable of stably supplying power while simultaneously increasing production is emerging. Furthermore, the need for high-capacity portable power is growing due to the performance improvements of electronic products, ranging from small devices such as mobile phones to medium-to-large devices such as electric vehicles. Lithium-ion batteries, which possess the highest potential, satisfy high-capacity power storage performance requirements and are therefore utilized in a wide range of applications, from small electronic devices to electric vehicles (EVs) and energy storage systems (ESS). The above lithium secondary battery generally consists of a positive electrode containing a positive active material, a negative electrode containing a negative active material, an electrolyte serving as a medium for transmitting lithium ions, and a separator. At this time, carbon-based active materials, silicon-based active materials, lithium transition metal oxides, lithium metal, etc., may be used as the negative active material. In addition, lithium transition metal oxides such as lithium cobalt oxide ( LiCoO2 ), lithium nickel oxide ( LiNiO2 ), lithium nickel-cobalt-manganese composite oxide, and lithium iron phosphate may be used as the positive active material. During the charging of a lithium secondary battery, lithium ions are generated from the positive electrode and can be converted into stacked or alloyed forms for storage on the negative electrode, while discharge proceeds in the opposite direction. Theoretically, the movement of lithium ions to the positive and negative electrodes during charging and discharging of such lithium secondary batteries should be reversible; however, in reality, the movement of lithium within the battery may be partially irreversible. Specifically, the medium through which lithium ions can move is the electrolyte. During charging, most lithium ions are stacked or alloyed within the negative electrode active material, but some are reduced together with the organic and inorganic materials constituting the electrolyte to form nano-sized organic-inorganic composites on the surface of the negative electrode material. This formed organic-inorganic film is called a solid electrolyte interface layer (SEI layer). Meanwhile, a solid electrolyte interface layer can also be formed on the surface of the positive electrode active material through the oxidation reaction of the materials constituting the electrolyte. While such a solid-electrolyte interface layer causes irreversible permanent loss of lithium ions supplied by the anode during formation, once formed, this irreversible loss is reduced, and a wide driving potential of the electrolyte is secured, enabling smooth reversible movement of lithium ions between the anode and cathode. Depending on its internal composition, this solid-electrolyte interface layer can contribute to lowering the energy barrier required for charge transfer of lithium ions to the cathode or anode, or its stability can determine the lifespan characteristics and durability of the lithium secondary battery. Meanwhile, as the application range of lithium secondary batteries expands to include not only portable power sources such as mobile phones, laptop computers, digital cameras, and camcorders, but also medium and large power sources such as power tools, electric bicycles, hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs), high driving voltages are required to achieve high energy density. However, when operating continuously under high voltage, not only is the electrolyte depleted due to oxidative decomposition reactions between the anode and the electrolyte, but the breakdown of the passivation film on the electrode surface also leads to problems such as gas generation from side reactions in the electrolyte and the leaching of transition metals from the anode, resulting in a deterioration of the battery's long-life performance. These problems are exacerbated or accelerated by exothermic reactions generated during battery operation. Accordingly, strengthening the stability of the solid-electrolyte interface layer formed on the surfaces of the anode and cathode is emerging as an important challenge to improve the high-voltage driving performance of lithium secondary batteries. The terms and words used in this specification and claims are used merely to describe exemplary embodiments and should not be interpreted as being limited to their ordinary or dictionary meanings, and should be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately def