Overview of the key role of sander in solid state battery applications.

March 12,2020

Overview of the key role of the sander in solid-state battery applications.

The sand mill is currently widely applicable, advanced, and efficient grinding equipment. The grinding chamber is narrow, the gap between the levers is small, and the grinding energy is dense. With the high-performance cooling system and automatic control system, continuous material discharge can be realized. , Which greatly improves production efficiency.

The current mainstream lithium batteries use liquid electrolytes, which have potential safety hazards such as fire and limited energy storage in a specific volume. The replacement of organic liquid electrolytes in traditional lithium-ion batteries with solid electrolytes can greatly alleviate safety issues and is expected to break through energy density. "Glass ceiling", solid-state batteries came into being. A solid battery is a battery that uses solid positive and negative electrodes and a solid electrolyte, does not contain any liquid, and all materials are composed of solid materials. According to forecasts, breakthroughs in solid-state battery technology research and development are expected to achieve breakthrough progress in 2020, further surpassing lithium-ion battery technology in terms of cost, energy density, and production process.

Of course, the production of solid-state batteries is also inseparable from sand mills. Below we take the solid electrolyte of the garnet structure as an example to introduce the application of sand mills in solid-state batteries.

Ta-doped Li7La3Zr2O12 (Ta-LLZO) garnet structure solid electrolyte has the advantages of high room temperature conductivity, stable lithium metal and can be prepared in air, etc. It is a candidate for the next generation of high-safety solid battery solid electrolyte materials. One. In its structure, Ta5 + replaces Zr4 + and introduces Li vacancies, which stabilizes the cubic phase on the one hand and improves the conductivity on the other. Among many methods for preparing Ta-LLZO powder, Solid State Reaction (SSR) is the most practical method for large-scale production of calcined powder. Before pressing and sintering, the calcined powder is generally ground to the sub-micron level to improve its sintering activity.

Figure F is a STEM photograph of a typical sanded Ta-LLZO particle. The surface of the sanded fine particles is rough, and the area marked by the white dotted frame is subjected to selective area electron diffraction (SAED). The result is shown in Figure G. The electron diffraction pattern is a polycrystalline Debye ring with obvious broadening, and the brightest ring corresponds to the (240) plane with a crystal plane spacing of 0.31 nm. The interplanar spacing is larger than that in the pure Ta-LLZO powder and the Ta-LLZO lattice after H + exchange. This shows that the surface and internal lattice of fine Ta-LLZO particles after sanding are deformed and polycrystalline. Figure H is an HRTEM atomic arrangement image of the particle surface. The image shows that Ta-LLZO is arranged in a very small domain (1 ~ 2nm), but the arrangement of different domains is completely disordered, further confirming the polycrystallization of the sanded particles, which is beneficial for subsequent sintering. sander machine.

(STEM of F: Ta-LLZO particles)

(Photo of Ta-LLZO particles of G: Ta-LLZO particles)

(HRTEM atomic arrangement image of H: Ta-LLZO particle surface)

It can be seen that the preparation process of the solid electrolyte is more refined, and the requirements for the particle size of the powder are higher. The traditional ball milling equipment is not sufficient to meet its requirements, so the production of the solid electrolyte cannot be separated from the sand mill.