CN-122025559-A - Tantalum-doped lithium metal composite negative electrode and preparation method thereof

Abstract

A tantalum-doped lithium metal composite negative electrode and a preparation method thereof comprise the steps of melting solid lithium metal into liquid lithium metal, adding the tantalum metal into the liquid lithium metal, mixing and stirring, standing and cooling to obtain a tantalum-doped lithium metal composite material, wherein the adding amount of the tantalum metal is 0.1-10wt% of the mass of the liquid lithium metal, and rolling the tantalum-doped lithium metal composite material to obtain the tantalum-doped lithium metal composite negative electrode, so that tantalum is introduced into the lithium metal through a melt doping process, and the formed tantalum-doped lithium metal composite negative electrode can inhibit growth of lithium dendrites and prolong the cycle life of a battery.

Inventors

• A RUHAN
• LI QINGWEN
• ZHANG SHIJUAN
• WANG XINYA
• LV YUANJIE
• XU ZHIHUI

Assignees

• 内蒙古工业大学

Dates

Publication Date

20260512

Application Date

20260213

Claims (9)

1. 1. The preparation method of the tantalum-doped lithium metal composite anode is characterized by comprising the following steps of: melting solid lithium metal into liquid lithium metal; Adding tantalum metal into liquid lithium metal, mixing and stirring, standing and cooling to obtain a tantalum-doped lithium metal composite material, wherein the adding amount of the tantalum metal is 0.1-10wt% of the mass of the liquid lithium metal; Rolling the tantalum-doped lithium metal composite material to obtain the tantalum-doped lithium metal composite anode.
2. 2. The method of preparing a tantalum-doped lithium metal composite anode according to claim 1, wherein said melting solid lithium metal into liquid lithium metal comprises: In an inert gas environment, heating the solid lithium metal to 200-300 ℃ to enable the solid lithium metal to be completely melted into liquid lithium metal.
3. 3. The method for preparing a tantalum-doped lithium metal composite anode according to claim 2, wherein the moisture content in the inert gas environment is less than or equal to 0.01ppm, the oxygen content is less than or equal to 0.01ppm, and the inert gas is nitrogen.
4. 4. The method of claim 1, wherein the solid lithium metal comprises one or more of a metal lithium sheet, a metal lithium block, and a metal lithium strip.
5. 5. The method for preparing a tantalum-doped lithium metal composite anode according to claim 1, wherein the tantalum metal comprises one or more of tantalum foil, tantalum powder and tantalum oxide.
6. 6. The method for preparing a tantalum-doped lithium metal composite anode according to claim 1, wherein the rolling treatment pressure is controlled to be 5-50 mpa, and the thickness of the tantalum-doped lithium metal composite anode is 10-1000 μm.
7. 7. The method for preparing the tantalum-doped lithium metal composite anode according to claim 1, wherein the stirring speed of the mixing and stirring is 10-500 r/min, the stirring time is 10-60 min, and the standing and cooling time is 30-120 min.
8. 8. The tantalum-doped lithium metal composite negative electrode prepared by the preparation method of the tantalum-doped lithium metal composite negative electrode according to any one of claim 17, wherein a gray interface layer is formed on the surface of the tantalum-doped lithium metal composite negative electrode through in-situ growth, and the gray interface layer prevents lithium metal from contacting electrolyte and reduces side reactions; tantalum metal is randomly distributed on the surface of the gray interface layer, a stable conductive network is formed by the distribution of the tantalum metal, the electric field distribution on the surface of the electrode is regulated, and lithium is guided to be uniformly deposited.
9. 9. A battery comprising the tantalum-doped lithium metal composite negative electrode according to claim 8 and a lithium iron phosphate positive electrode.

Description

Tantalum-doped lithium metal composite negative electrode and preparation method thereof Technical Field The invention relates to the technical field of lithium batteries, in particular to a tantalum-doped lithium metal composite negative electrode and a preparation method thereof. Background The secondary lithium battery is increasingly widely applied in the fields of electric automobiles, energy storage equipment and the like, and has higher requirements on the energy density, the cycling stability and the safety of the battery. Metallic lithium has an extremely high theoretical specific capacity (3830 mAhg -1) and the lowest electrode potential (-3.04 Vvs. Standard hydrogen electrode), and is considered to be the most potential negative electrode material for secondary lithium batteries. The pure lithium metal negative electrode has the following problems that lithium dendrites are easy to form in the deposition/stripping process of lithium metal, and the growth of the lithium dendrites can puncture a battery diaphragm, so that the battery is short-circuited, and potential safety hazards are caused. The lithium metal surface has active chemical property, is easy to generate side reaction with electrolyte, consumes the electrolyte and lithium metal, and reduces the coulombic efficiency of the battery. The lithium metal has huge volume expansion/contraction (more than 300 percent) in the circulating process, so that the electrode structure is damaged and pulverized, and the circulating life of the battery is shortened. Disclosure of Invention The invention aims to provide a tantalum-doped lithium metal composite anode and a preparation method thereof, wherein tantalum is introduced into lithium metal through a melt doping process, and the formed tantalum-doped lithium metal composite anode can inhibit growth of lithium dendrites and prolong the cycle life of a battery. In order to achieve the above purpose, the first aspect of the present invention provides a method for preparing a tantalum-doped lithium metal composite anode, comprising melting solid lithium metal into liquid lithium metal, adding tantalum metal into the liquid lithium metal, mixing and stirring, standing and cooling to obtain a tantalum-doped lithium metal composite material, wherein the adding amount of the tantalum metal is 0.1-10wt% of the mass of the liquid lithium metal, and rolling the tantalum-doped lithium metal composite material to obtain the tantalum-doped lithium metal composite anode. In one embodiment of the invention, the melting of solid lithium metal to liquid lithium metal includes heating the solid lithium metal to 200-300 ℃ in an inert gas environment to completely melt the solid lithium metal to liquid lithium metal. In one embodiment of the invention, the moisture content in the inert gas environment is less than or equal to 0.01ppm, the oxygen content is less than or equal to 0.01ppm, and the inert gas is nitrogen. In one embodiment of the invention, the solid lithium metal comprises one or more of a metallic lithium sheet, a metallic lithium block, a metallic lithium strip. In one embodiment of the invention, the tantalum metal comprises one or more of tantalum foil, tantalum powder, tantalum oxide. In one embodiment of the invention, the rolling treatment pressure is controlled to be 5-50 MPa, and the thickness of the tantalum-doped lithium metal composite anode is 10-1000 mu m. In one embodiment of the invention, the stirring speed of the mixing and stirring is 10-500 r/min, the stirring time is 10-60 min, and the standing and cooling time is 30-120 min. The second aspect of the invention provides a tantalum-doped lithium metal composite anode, wherein a gray interface layer is formed on the surface of the tantalum-doped lithium metal composite anode through in-situ growth, the gray interface layer prevents lithium metal from contacting electrolyte, side reaction is reduced, tantalum metal is randomly distributed on the surface of the gray interface layer, a stable conductive network is formed by the distribution of the tantalum metal, the electric field distribution on the surface of an electrode is regulated, and lithium is guided to be uniformly deposited. In a third aspect of the present invention, a battery is provided that combines a tantalum doped lithium metal composite negative electrode with a lithium iron phosphate positive electrode to form a battery. The invention has the beneficial effects that: tantalum is introduced into a lithium metal anode in a melt doping mode, and the electrochemical performance of the lithium metal anode is remarkably improved by utilizing the high chemical stability and conductivity of tantalum and the stable mixing effect brought by a tantalum lithium melting area, The surface of the tantalum-doped lithium metal composite anode forms a gray interface layer formed by lithium-tantalum alloy through in-situ reaction, so that the contact between electrolyte and lithium metal