EP-4742326-A1 - ELECTRODE ADDITIVE, NEGATIVE ELECTRODE COMPRISING SAME FOR LITHIUM SECONDARY BATTERY, AND METHOD FOR MANUFACTURING NEGATIVE ELECTRODE FOR LITHIUM SECONDARY BATTERY

Abstract

The present invention relates to an electrode additive, an anode for a lithium secondary battery including the same, and a method for manufacturing an anode for a lithium secondary battery. The electrode additive of the present invention mitigates damage due to volume change of the anode active material and can improve the phenomenon of energy density reduction of the battery without reducing the density of the electrode. Furthermore, it is dissociated into an alkali cation and a carbon-based anion like an ionic compound in the electrolyte to compensate for cation loss in the electrolyte, thereby remarkably improving the capacity retention performance.

Inventors

• KIM, HANSU
• KIM, JUNHO
• LEE, Jiwhan
• SHIN, IK SOO

Assignees

• Graphenide Technology Co., Ltd.

Dates

Publication Date

20260513

Application Date

20240703

Claims (20)

1. An electrode additive comprising a composite of a carbon material including an oxygen-containing functional group; and lithium.
2. The electrode additive according to claim 1, characterized in that the lithium is bonded to the oxygen-containing functional group.
3. The electrode additive according to claim 1, characterized in that the oxygen-containing functional group is one or more of a hydroxyl group, an ether group, an aldehyde group, an epoxy group, an amide group, a carboxyl group, and a ketone group.
4. The electrode additive according to claim 1, characterized in that the carbon material is one or more of graphene quantum dots, graphene, graphene oxide, carbon black, carbon nanotubes, graphite, fullerene, and carbon nanofiber.
5. The electrode additive according to claim 1, characterized in that the lithium is included in an amount of 8 to 20 wt% based on 100 wt% of the total electrode additive.
6. The electrode additive according to claim 1, characterized in that the size of the carbon material is 12 nm or less.
7. An anode for a lithium secondary battery, comprising the electrode additive according to any one of claims 1 to 6; and an anode active material.
8. The anode for a lithium secondary battery according to claim 7, characterized in that the anode active material includes one or more of silicon (Si), tin (Sn), germanium (Ge), an oxide thereof, an alloy thereof, and a combination thereof.
9. The anode for a lithium secondary battery according to claim 7, characterized in that the weight ratio of the anode active material and the electrode additive is 100:1 to 8.
10. The anode for a lithium secondary battery according to claim 7, characterized by further comprising a binder.
11. The anode for a lithium secondary battery according to claim 7, characterized by further comprising a conductive material.
12. A lithium secondary battery comprising the anode according to any one of claims 7 to 11.
13. A capacitor comprising the anode according to any one of claims 7 to 11.
14. A method for manufacturing an anode for a lithium secondary battery, comprising: (I) preparing an electrode additive by mixing a carbon material including an oxygen-containing functional group and a lithium precursor; (II) preparing an anode slurry by adding the electrode additive obtained in the step (I) and the anode active material to a solvent; and (III) applying and drying the anode slurry.
15. The method for manufacturing an anode for a lithium secondary battery according to claim 14, characterized in that the oxygen-containing functional group is one or more of a hydroxyl group, an ether group, an aldehyde group, an epoxy group, an amide group, a carboxyl group, and a ketone group.
16. The method for manufacturing an anode for a lithium secondary battery according to claim 14, characterized in that the carbon material is one or more of graphene quantum dots, graphene, graphene oxide, carbon black, carbon nanotubes, graphite, fullerene, and carbon nanofiber.
17. The method for manufacturing an anode for a lithium secondary battery according to claim 14, characterized in that the lithium precursor is one or more of lithium hydroxide, lithium carbonate, lithium sulfate, lithium oxide, and lithium chloride.
18. The method for manufacturing an anode for a lithium secondary battery according to claim 14, characterized in that the lithium is included in an amount of 8 to 20 wt% based on 100 wt% of the total electrode additive.
19. The method for manufacturing an anode for a lithium secondary battery according to claim 14, characterized in that the weight ratio of the anode active material and the electrode additive is 100:1 to 8.
20. The method for manufacturing an anode for a lithium secondary battery according to claim 14, characterized in that the anode slurry further comprises a binder.

Description

BACKGROUND 1. Field The present invention relates to an electrode additive, an anode for a lithium secondary battery including the same, and a method for manufacturing an anode for a lithium secondary battery. 2. Description of Related Art The scope of utilization of lithium secondary batteries is gradually expanding, ranging from small electronic devices such as conventional smartphones to new and renewable energy storage systems and energy storage sources capable of driving electric vehicles. Particularly, in order to solve energy and environmental problems, research to utilize renewable energy sources such as electric vehicles, solar heat, solar light, and wind energy is actively progressing, and thus, large-scaling of batteries used for this purpose is required. Lithium-ion secondary batteries are the most promising batteries capable of driving this, but in the case of lithium-ion batteries employing currently commercialized graphite as a main anode material for a lithium secondary battery, many parts need to be improved to satisfy the performance required by the market due to low theoretical capacity. Especially in the case of electric vehicles replacing internal combustion engine automobiles, the distance that batteries at the current level can travel on a single charge is unsatisfactory compared to internal combustion engines, and thus, an anode having high energy density and long lifespan performance is required. Accordingly, anode active material materials such as silicon (Si), tin (Sn), and germanium (Ge) which can exhibit high capacity by alloying with lithium during charging of the battery and dealloying during discharging are receiving great attention. Particularly, while graphite stores 1 lithium ion per 6 carbon atoms, silicon can store 4.4 lithium ions per 1 silicon atom, so silicon dramatically improves energy density (capacity increases by 10 times or more compared to graphite), which is advantageous for not only increasing the driving distance of electric vehicles but also for the fast charging design of batteries. Furthermore, silicon is an economical and eco-friendly material. Accordingly, silicon is drawing attention as a next-generation anode material that has overcome the capacity limitations of graphite anode material and escaped from the absolute dependence on China for graphite, and is actually used in the form of an additive of about 5 wt% or less of graphite anode material. However, silicon undergoes repeated volume expansion and contraction due to alloying and dealloying during charging and discharging, resulting in the generation of cracks and fracture of particles as charging and discharging proceed, and gradually decreasing capacity, which is disadvantageous in that the lifespan characteristic is not excellent. In order to solve these problems, methods for manufacturing an electrode using the active material oxide, methods for suppressing volume change through structural improvement or active material coating of the active material, and methods for improving the performance of a binder of the electrode have been studied, but the effects were insignificant. Accordingly, the present inventors have found that by introducing a composite of a carbon material including an oxygen-containing functional group and lithium into an anode for a lithium secondary battery, it can be dissociated like an ionic compound to compensate for the loss of lithium, and the phenomenon of peeling or cracking due to the volume change of the active material can be remarkably improved, thereby improving the electrochemical performance of the lithium secondary battery, leading to the completion of the present invention. SUMMARY The present invention was devised to solve the above problems, and an object of the present invention is to compensate for cation loss by being dissociated in an electrolyte and to bond with a binder, thereby improving the mechanical strength of the electrode and remarkably improving damage due to volume expansion of the anode active material, and to provide an electrode additive including a composite of a carbon material including an oxygen-containing functional group and lithium, and an anode for a lithium secondary battery including the same. One aspect of the present invention provides an electrode additive including a composite of a carbon material including an oxygen-containing functional group; and lithium. Another aspect of the present invention provides an anode for a lithium secondary battery including the electrode additive; and an anode active material. Still another aspect of the present invention provides a lithium secondary battery including the anode. Still another aspect of the present invention provides a capacitor including the anode. Still another aspect of the present invention provides a method for manufacturing an anode for a lithium secondary battery, including: (I) preparing an electrode additive by mixing a carbon material including an oxygen-containing fu