CN-116864798-B - Interface layer with high diffusion coefficient, preparation method thereof and battery

Abstract

The invention discloses an interface layer with high diffusion coefficient, wherein the raw materials of the interface layer comprise carbon materials and organic compounds with thioamide groups. The interface layer can effectively reduce the local current density of the anode, improve the diffusion capacity of Li + in the anode, prevent charge accumulation, promote Li + to be timely supplemented, and further avoid the growth of Li dendrites. The interface layer is used in the battery, so that the electrical property and the safety performance of the battery can be improved.

Inventors

• WU FAN
• WANG ZHIXUAN

Assignees

• 天目湖先进储能技术研究院有限公司
• 长三角物理研究中心有限公司
• 中国科学院物理研究所

Dates

Publication Date

20260508

Application Date

20230724

Claims (17)

1. 1. An interface layer with high diffusion coefficient, characterized in that the interface layer has characteristic peaks of 25 degrees, 44 degrees and 45 degrees in an X-ray powder diffraction pattern expressed in terms of diffraction angle 2 theta; the raw materials of the interface layer comprise carbon materials, organic compounds with thioamide groups and film forming agents; the thioamide group has the structural formula I: (structural formula I).
2. 2. An interfacial layer having a high diffusion coefficient according to claim 1, wherein the mass ratio of said carbon material and said organic compound having a thioamide group is 1 (0.125-1).
3. 3. An interfacial layer having a high diffusion coefficient according to claim 1, wherein the mass ratio of said carbon material and said organic compound having a thioamide group is 1 (0.5-1).
4. 4. The interfacial layer of claim 1 wherein said carbon material comprises one or more of soft carbon and hard carbon, said organic compound having a thioamide group comprises one or more of thiourea and thioacetamide, and said film former comprises one or more of polytetrafluoroethylene, polyethylene, polyhexafluoropropylene, styrene-butadiene rubber.
5. 5. The interface layer of claim 4, wherein the soft carbon comprises one or more of graphite, petroleum coke, needle coke, carbon fiber, and carbon microsphere, and the hard carbon comprises one or more of resinous carbon, organic polymeric carbon, carbon black, and biomass carbon.
6. 6. An interface layer having a high diffusion coefficient according to claim 1, wherein the interface layer has a thickness of 25 μm to 35 μm.
7. 7. A method of preparing the interfacial layer of any one of claims 1-6, wherein the method of preparing comprises: Weighing and mixing carbon materials and organic compounds with thioamide groups according to the mass ratio, calcining the mixed carbon materials and organic compounds with thioamide groups in inert atmosphere to obtain a compound, mixing the compound with a film forming agent, and rolling and forming a film by a dry method to obtain an interface layer.
8. 8. The method of claim 7, wherein the mass ratio of the complex to the film former is 100:3; the calcination temperature is 300-500 ℃, and the calcination time is 4-6 h; the inert atmosphere comprises one of nitrogen, argon, helium, neon, krypton and xenon.
9. 9. A metal-containing lithium anode comprising the interfacial layer of any one of claims 1-6.
10. 10. A cathode comprising the interfacial layer of any one of claims 1-6.
11. 11. A separator comprising the interfacial layer of any one of claims 1-6.
12. 12. The metal-containing lithium anode of claim 9, wherein the metal-containing lithium anode comprising the interfacial layer has a loading of 5mAh cm -2 or more area capacity.
13. 13. The metal-containing lithium anode of claim 9, wherein the metal-containing lithium anode comprising the interfacial layer has a loading of 15mAh cm -2 or more area capacity.
14. 14. The metal-containing lithium anode of claim 9, wherein the metal-containing lithium anode comprising the interfacial layer has a loading of 20mAh cm -2 or more area capacity.
15. 15. A battery comprising the interfacial layer of any one of claims 1-6.
16. 16. The battery of claim 15, wherein the battery comprises a sulfide all-solid-state lithium metal battery.
17. 17. An electrochemical device comprising the interfacial layer of any one of claims 1-6.

Description

Interface layer with high diffusion coefficient, preparation method thereof and battery Technical Field The invention relates to the technical field of materials, in particular to an interface layer with a high diffusion coefficient, a preparation method thereof and a battery. Background In recent years, attention has been paid to an all-solid-state battery with high safety. Sulfide Solid State Electrolytes (SSEs) with the highest ionic conductivity (1-25 mS cm -1) and desirable mechanical properties, as well as better interfacial contact with active materials, are considered one of the most promising SSEs. With the lowest redox potential (3.04V compared to standard hydrogen electrodes) and the ultra-high specific capacity (3860 mAh g -1), metallic lithium is the most promising anode for achieving high energy density of all-solid-state batteries (ASSBs). Therefore, sulfide all-solid state lithium metal batteries (ASSLMBs) employing a sulfide electrolyte and a lithium metal anode are most promising for achieving the goals of high safety and high energy density. However, the growth of lithium dendrites in the spinners has long limited the development of ASSLMBs. The growth of lithium dendrites is mainly caused by several reasons. First, the low binding strength, low surface energy and high fluidity of lithium make it susceptible to one-dimensional whisker growth. Second, metallic lithium tends to form voids with the SSE during exfoliation, resulting in poor interfacial contact, large interfacial resistance, uneven charge distribution, and high overpotential, which exacerbates Li dendrite formation. To address the interface problem, researchers have developed a number of interface protection layers to improve the interface problem. Researchers have employed ZnO, al 4Li9, liF, ag-C, and graphite layers to wet the interface and provide deposition points for lithium, however, the current density and area capacity achievable with ASSLMBs is still insufficient for commercial applications. This is mainly because the formation of Li dendrites is also determined by the reduction rate of Li + and their replenishment around the electrode. At high current densities, the opportunity for Li dendrites to form increases greatly due to the faster rate of Li + reduction to Li. If Li + is not timely replenished, localized charge accumulation can occur, thereby inducing growth of the Li dendrite. Lithium deposition in ASSLMBs occurs only at the anode-SSE interface, further increasing the risk of charge accumulation, thus greatly limiting the rate performance of ASSLMBs. Therefore, constructing a three-dimensional metallic lithium anode, so that the deposition of metallic lithium is not limited to the interface between the anode and the electrolyte, is an effective way to inhibit the growth of lithium dendrites, thereby improving the rate performance of the battery. The main reason for causing deposition of metallic lithium at the interface between the electrolyte and the anode is that the diffusion coefficient of Li + in the anode is low, which results in that Li + cannot be transported inside the anode and electrons are directly obtained at the interface. Therefore, the primary task of developing dendrite-free ASSLMB is to design lithium metal anodes with high ion diffusion coefficients and electron conductivities. Disclosure of Invention Aiming at the problems in the prior art, the invention discloses an interface layer with a high diffusion coefficient, which can effectively reduce the local current density of a metal-containing lithium anode, improve the diffusion capacity of Li + on the metal-containing lithium anode, prevent charge accumulation, promote Li + to be timely supplemented, and further avoid the growth of Li dendrites. The interface layer is used in the battery, so that the electrical property and the safety performance of the battery can be improved. The invention is realized by the following technical scheme: the invention provides an interface layer with a high diffusion coefficient, wherein raw materials of the interface layer comprise carbon materials and organic compounds with thioamide groups. According to the design, S and N in the thioamide group (structural formula I) are doped in a carbon material to form C-N and C-S bonds, and the C-N and C-S bonds can further reduce the transmission energy barrier of Li +, so that the diffusion rate of Li + is remarkably improved, and therefore Li + can diffuse to the whole interface layer to obtain electrons to form metallic lithium. The mode of depositing the metallic lithium in the interface layer can effectively reduce the local current density of the anode, prevent charge accumulation, and make Li + be timely supplemented, thereby avoiding the growth of Li dendrites. Therefore, the interface layer can improve the lithium ion diffusivity of the metal-containing lithium anode, and can reduce the formation of lithium dendrites, thereby improving the electrical pro