KR-20260066630-A - ELECTROLYTE ADDITIVE, NON-AQUEOUS ELECTROLYTE FOR SECONDARY BATTERY AND SECONDARY BATTERY COMPRISING THE SAME

Abstract

The present invention provides an electrolyte additive, a non-aqueous electrolyte for a secondary battery containing the same, and a lithium secondary battery. Specifically, the present invention provides an electrolyte additive comprising a compound represented by the following chemical formula 1 capable of forming a film with excellent mechanical durability on the surface of the positive electrode, a non-aqueous electrolyte for a secondary battery containing the same, and a lithium secondary battery. [Chemical Formula 1] In the above chemical formula 1, R is an alkylene group having 1 to 5 carbon atoms.

Inventors

• 서수민
• 이철행
• 안경호
• 오영호
• 정유경
• 임태영
• 홍다영

Assignees

• 주식회사 엘지에너지솔루션

Dates

Publication Date

20260512

Application Date

20251029

Priority Date

20241104

Claims (11)

1. Electrolyte additive comprising a compound represented by the following chemical formula 1: [Chemical Formula 1] In the above chemical formula 1, R is an alkylene group having 1 to 5 carbon atoms.
2. In paragraph 1, In the above chemical formula 1, R is an electrolyte additive having 1 to 3 carbon atoms and is an alkylene group.
3. In paragraph 1, The electrolyte additive represented by the above chemical formula 1 is at least one selected from the group consisting of compounds represented by the following chemical formulas 1A to 1C: [Chemical Formula 1A] [Chemical Formula 1B] [Chemical Formula 1C] .
4. A non-aqueous electrolyte for a secondary battery comprising the electrolyte additive of claim 1.
5. In paragraph 4, The above electrolyte additive is included in an amount of 0.05% to 9% by weight based on the total weight of the above non-aqueous electrolyte for a secondary battery.
6. In paragraph 4, The above electrolyte additive is included in an amount of 0.05% to 5% by weight based on the total weight of the above non-aqueous electrolyte for a secondary battery.
7. In paragraph 4, The above-mentioned non-aqueous electrolyte for a secondary battery is a non-aqueous electrolyte for a secondary battery that further comprises a lithium salt and an organic solvent.
8. In paragraph 4, The above-mentioned non-aqueous electrolyte for a secondary battery 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, silane compounds, and lithium salt compounds.
9. anode; A cathode facing the anode above; A separator interposed between the above cathode and the above anode; and A lithium secondary battery comprising a non-aqueous electrolyte for a secondary battery according to claim 4.
10. In Paragraph 9, The above-mentioned positive electrode includes a positive electrode active material, and The above positive active material is a lithium secondary battery containing lithium iron phosphate.
11. In Paragraph 10, The above positive active material is a lithium secondary battery further comprising a lithium nickel-cobalt-manganese composite oxide.

Description

Electrolyte additive, non-aqueous electrolyte for secondary battery comprising the same, and lithium secondary battery The present invention relates to an electrolyte additive, a non-aqueous electrolyte for a secondary battery containing the same, and a lithium secondary battery. 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 is generally composed of a positive electrode containing a positive active material, a negative electrode containing a negative active material, an electrolyte that serves 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 electrode 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 electrode 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. Although the formation of such a solid-electrolyte interface layer causes irreversible loss of lithium ions supplied by the anode, once the layer is 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 charging and discharging of the lithium secondary battery progresses, the deterioration of the initially formed solid-electrolyte interface layer causes the decomposition of the electrolyte, leading to an increase in resistance and structural degradation of the cathode material, which results in the leaching of transition metals from the cathode. The transition metal ions leached out in this way are re-deposited on the cathode, which causes an increase in the resistance of the cathode. Conversely, they move through the electrolyte to the anode and are electrodeposited on the anode, causing self-discharge of the anode. Furthermore, due to the destruction and regeneration of the solid-electrolyte interface layer, additional lithium ions are consumed, which causes an increase in resistance and a deterioration of lifespan. Therefore, strengthening the stability of the solid-electrolyte interface layer is emerging as an important task to improve the performance of lithium secondary batteries. First, prior to describing the present invention, 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. Instead, they 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 define the conc