Preparation of all-solid-state lithium batteries by solution immersion process -Lithium - Ion Battery Equipment
With the continuous development of lithium-ion battery technology, the pursuit of energy density is getting higher and higher. In the latest national guidelines for new energy vehicles, it is proposed that by 2020, the specific energy of a single power battery should reach 300Wh/ kg, it is very difficult to achieve this indicator on the existing lithium-ion battery system. At the just-held 3rd New Battery Positive and Negative Material Technology Estimation Forum, researcher Liu Jun from the Pacific Northwest National Laboratory of the United States proposed that there are two main methods for developing batteries with a specific energy of 500Wh/kg in the future: high-nickel NCM And the metal lithium system, the other is the lithium-sulfur battery system, no matter which method is used, we cannot avoid metal lithium. The biggest problem with lithium metal as a lithium-ion battery is the generation and growth of lithium dendrites. Although some studies have shown that ether solvent electrolytes can effectively inhibit the generation of lithium dendrites, due to the low decomposition voltage of ether compounds, And it has strong flammability, so it is difficult to apply in commercial lithium-ion batteries. From the current point of view, for lithium-ion batteries using metal lithium negative electrodes, all-solid-state electrolytes are a more feasible way, and solid-state electrolytes have higher The elastic modulus can well inhibit the generation and growth of lithium dendrites, so it can effectively improve the cycle life and safety performance of metal lithium batteries.(Lithium - Ion Battery Equipment)
At present, solid-state electrolytes are mainly divided into two categories: inorganic ceramic electrolytes and organic polymer electrolytes. Among them, sulfide solid electrolytes are the most attractive because of their high lithium ion conductivity (10-2S/cm) and good flexibility. However, the sulfide solid electrolyte is easy to react with polar solvents, and its micronized characteristics will also make it difficult to homogenize the positive and negative electrodes. In order to solve this problem, DongHyeon Kim from Ulsan University in South Korea proposed a new method for large-scale preparation of all-solid-state batteries. ) ethanol or 0.4LiI-0.6Li4SnS4 methanol solution to infiltrate the traditional lithium-ion battery electrode, the battery shows a high reversible capacity, the positive electrode LiCoO2 reached 141mAh/g, and the negative electrode graphite material reached 364mAh/g (0.1C, 30°C), and the battery also exhibited good electrochemical performance at 100°C, indicating that the battery has good thermal stability and safety.
The production of traditional solid-state lithium-ion batteries requires a more complicated dry-mixing process to mix active materials, solid-state electrolytes, conductive agents, and binders. However, in actual processes, we prefer to use wet-mixing processes to mix these electrode components, but Due to the strong reactivity of solid electrolytes and polar solvents, the polar solvents used in the traditional lithium-ion battery production process cannot be used in the production of all-solid-state lithium-ion batteries, so we need to develop a non-polar solvent for For the production of all-solid lithium-ion batteries, such as toluene and xylene, and traditional binders, such as PVDF, CMC, SBR, etc. are not suitable for all-solid electrolytes, so it is necessary to develop a suitable binder. In addition, for lithium-ion batteries, the homogenization process needs to mix the three substances evenly (active material, conductive agent, binder), while for all-solid-state batteries, a solid electrolyte is also added, not only the electrodes must be considered Electronic conductivity, but also the ionic conductivity of the electrode. In general, the preparation process of all-solid-state electrolyte electrodes is far more complicated than that of lithium-ion batteries.
In order to make the various components of the electrode of the all-solid-state lithium-ion battery uniformly mixed, DongHyeonKim et al. first obtained the electrode sheet of the lithium-ion battery by using the traditional process, and then made the solid electrolyte Li6PS5Cl and 0.4LiI-0.6Li4SnS4 into ethanol and methanol solution, the lithium-ion battery pole piece is immersed in the above solution, and then dried and rolled, this process ensures the uniform mixing between the solid electrolyte and the active material, and ensures the good electrochemical performance of the battery. The reversible capacity of the positive electrode LiCoO2 reached 141mAh/g, and the negative electrode graphite material reached 364mAh/g (0.1C, 30°C, half-cell). At the same time, the battery also showed good electrochemical performance at 100°C. It shows that the battery has good thermal stability and safety.
At present, solid-state electrolytes are mainly divided into two categories: inorganic ceramic electrolytes and organic polymer electrolytes. Among them, sulfide solid electrolytes are the most attractive because of their high lithium ion conductivity (10-2S/cm) and good flexibility. However, the sulfide solid electrolyte is easy to react with polar solvents, and its micronized characteristics will also make it difficult to homogenize the positive and negative electrodes. In order to solve this problem, DongHyeon Kim from Ulsan University in South Korea proposed a new method for large-scale preparation of all-solid-state batteries. ) ethanol or 0.4LiI-0.6Li4SnS4 methanol solution to infiltrate the traditional lithium-ion battery electrode, the battery shows a high reversible capacity, the positive electrode LiCoO2 reached 141mAh/g, and the negative electrode graphite material reached 364mAh/g (0.1C, 30°C), and the battery also exhibited good electrochemical performance at 100°C, indicating that the battery has good thermal stability and safety.
The production of traditional solid-state lithium-ion batteries requires a more complicated dry-mixing process to mix active materials, solid-state electrolytes, conductive agents, and binders. However, in actual processes, we prefer to use wet-mixing processes to mix these electrode components, but Due to the strong reactivity of solid electrolytes and polar solvents, the polar solvents used in the traditional lithium-ion battery production process cannot be used in the production of all-solid-state lithium-ion batteries, so we need to develop a non-polar solvent for For the production of all-solid lithium-ion batteries, such as toluene and xylene, and traditional binders, such as PVDF, CMC, SBR, etc. are not suitable for all-solid electrolytes, so it is necessary to develop a suitable binder. In addition, for lithium-ion batteries, the homogenization process needs to mix the three substances evenly (active material, conductive agent, binder), while for all-solid-state batteries, a solid electrolyte is also added, not only the electrodes must be considered Electronic conductivity, but also the ionic conductivity of the electrode. In general, the preparation process of all-solid-state electrolyte electrodes is far more complicated than that of lithium-ion batteries.
In order to make the various components of the electrode of the all-solid-state lithium-ion battery uniformly mixed, DongHyeonKim et al. first obtained the electrode sheet of the lithium-ion battery by using the traditional process, and then made the solid electrolyte Li6PS5Cl and 0.4LiI-0.6Li4SnS4 into ethanol and methanol solution, the lithium-ion battery pole piece is immersed in the above solution, and then dried and rolled, this process ensures the uniform mixing between the solid electrolyte and the active material, and ensures the good electrochemical performance of the battery. The reversible capacity of the positive electrode LiCoO2 reached 141mAh/g, and the negative electrode graphite material reached 364mAh/g (0.1C, 30°C, half-cell). At the same time, the battery also showed good electrochemical performance at 100°C. It shows that the battery has good thermal stability and safety.
