CN-122025651-A - Modified copper current collector, negative electrode plate containing modified copper current collector and secondary battery

Abstract

The application discloses a modified copper current collector, a negative electrode plate and a secondary battery containing the modified copper current collector, and belongs to the technical field of electrochemical energy storage. According to the modified copper current collector, the functional coating is introduced to at least one surface of the copper current collector, the functional coating comprises okra extract and aloe gel, damage of puncture of lithium dendrite to a negative electrode plate can be effectively reduced through cooperation of the okra extract and the aloe gel, meanwhile, ionic conductivity can be remarkably improved through compounding of the okra extract and the aloe gel, and a battery prepared subsequently has good cycle performance and coulombic efficiency retention rate.

Inventors

• ZHOU LEI
• SONG SHANSHAN
• ZOU ZHILIN
• WANG YIWEI
• XU ZEYANG

Assignees

• 成都工业学院

Dates

Publication Date

20260512

Application Date

20260128

Claims (10)

1. 1. A modified copper current collector, characterized in that the modified copper current collector comprises a copper current collector and a functional coating arranged on at least one surface of the copper current collector; The functional coating comprises okra extract and aloe gel; the okra extract is obtained by water extraction.
2. 2. The modified copper current collector of claim 1, wherein the functional coating has a thickness of 5-15 μm.
3. 3. The modified copper current collector according to claim 1, wherein the volume ratio of okra extract to aloe vera gel is 1 (0.6-1.4).
4. 4. The modified copper current collector according to claim 1, wherein the preparation method of the okra extract comprises the steps of extracting pretreated okra in water, filtering after the extraction is finished, and collecting filtrate to obtain the okra extract.
5. 5. The modified copper current collector of claim 4, wherein the mass to volume ratio of okra to water is 1g (6-11) mL.
6. 6. The modified copper current collector of claim 4, wherein the extraction is a heated extraction, the heated extraction temperature is 50-70 ℃, and the heated extraction time is 30-60 minutes; And/or the extraction is ultrasonic extraction, the ultrasonic power is 400-600W, and the ultrasonic time is 20-40min.
7. 7. The modified copper current collector according to claim 1, wherein the aloe gel is prepared by peeling aloe to obtain mesophyll.
8. 8. The method for preparing a modified copper current collector according to any one of claims 1 to 7, comprising the steps of mixing okra extract and aloe gel, coating the surface of the pretreated copper current collector, and drying at 45 to 55 ℃ for 1.5 to 2.5 hours to obtain the modified copper current collector.
9. 9. A negative electrode sheet comprising the modified copper current collector of any one of claims 1-7.
10. 10. A secondary battery comprising the negative electrode tab of claim 9.

Description

Modified copper current collector, negative electrode plate containing modified copper current collector and secondary battery Technical Field The application relates to the technical field of electrochemical energy storage, in particular to a modified copper current collector, a negative electrode plate containing the modified copper current collector and a secondary battery. Background Commercial lithium ion batteries commonly employ graphite/copper foil negative electrode systems, while copper current collectors are widely used as negative electrode substrates in lithium metal batteries by virtue of their high conductivity and well-established mass production processes, their intrinsic interface defects severely hamper the development of high performance batteries. Specifically, the first aspect is the problem of dendrite runaway, namely that the difference of crystal lattice orientations on the surface of the copper foil easily causes larger potential difference of crystal face deposition, so that local current density is not uniform, and dendrites are promoted to penetrate through SEI film after circulation. The second aspect is the volume effect failure problem in that the lithium metal deposition/exfoliation process creates a volume change that accumulates at the interface, causing the active material to delaminate and form a "dead lithium" layer, which attenuates the battery capacity. The third aspect is the limitation of traditional modification, namely the existing copper foil surface coating technology can not adapt to volume deformation. Meanwhile, the existing technology for introducing the coating also has a series of problems to be solved. For example, the existing vapor deposition/nano coating process has the problems of complexity and high cost, for example, the traditional polymer coating interface has insufficient mechanical flexibility, can not inhibit lithium dendrite puncture and cyclic stress damage, so as to lead to coulomb efficiency attenuation, for example, toxic solvents (such as NMP) bring environmental protection risks, and 90% of traditional adhesives use NMP (N-methylpyrrolidone) as a reproduction toxic substance. Therefore, there is a need to develop a copper current collector which is simple in process, low in cost, green and environment-friendly, and can effectively improve lithium dendrite penetration and the capacity degradation of a secondary battery. Disclosure of Invention The application aims to solve the problems of fast capacity attenuation and fast coulomb efficiency attenuation of a secondary battery caused by out-of-control lithium dendrite, volume effect failure and the like in a copper current collector in the prior art, and provides a modified copper current collector which is environment-friendly, simple in process operation, capable of effectively reducing penetration of lithium dendrite and volume effect failure, and further capable of effectively improving capacity retention rate and coulomb efficiency retention rate of the secondary battery, and a negative electrode plate and the secondary battery comprising the modified copper current collector. To achieve the above object, a first aspect of the present application is a modified copper current collector including a copper current collector, and a functional coating layer provided on at least one surface of the copper current collector; The functional coating comprises okra extract and aloe gel; the okra extract is obtained by water extraction. As an embodiment of the present application, the functional coating has a thickness of 5-15 μm. As an embodiment of the application, the volume ratio of okra extract to aloe vera gel is 1 (0.6-1.4). The preparation method of the okra extract comprises the steps of extracting pretreated okra in water, filtering after the extraction is finished, and collecting filtrate to obtain the okra extract. As an embodiment of the application, the mass volume ratio of the okra to the water is 1g (6-11) mL. As an embodiment of the application, the extraction is a heated extraction, the heated extraction temperature is 50-70 ℃ and the heated extraction time is 30-60min. As an embodiment of the application, the extraction is ultrasonic extraction, the ultrasonic power is 400-600W, and the ultrasonic time is 20-40min. As an embodiment of the application, the aloe gel is prepared by peeling aloe to obtain mesophyll and obtaining aloe gel. In the second aspect of the application, the preparation method comprises the steps of mixing okra extract and aloe gel, coating the mixture on the surface of a pretreated copper current collector, and then drying the copper current collector at 45-55 ℃ for 1.5-2.5 hours to obtain the modified copper current collector. In a third aspect of the application, there is provided a negative electrode tab comprising the modified copper current collector of the application. In a fourth aspect of the present application, a secondary battery is provided, co