German researchers use tomography to study copper sulfide solid-state batteries

2024-01-22

Solid State Battery (SSB) is currently considered one of the promising battery technologies in the future. Compared to lithium-ion batteries currently used in mobile phones, laptops, and electric vehicles, SSB can achieve higher energy density and better safety. Therefore, in addition to research institutions, major automotive companies are also researching this technology.

The main feature of this technology is to replace highly flammable liquid electrolytes in lithium-ion batteries with solid ones. Therefore, the entire battery is only composed of "solid materials", hence the name solid-state battery. In order to produce this type of battery, different materials (anode, cathode, and electrolyte) must be pressed together under high pressure.

According to foreign media reports, researchers from the Helmholtz Zentrum Berlin and Hereon Research Center, Humboldt University ä t zu Berlin, and the Federal Institute for Materials Research and Testing have successfully observed the charging and discharging processes of this solid-state battery. A team led by Professor Philipp Adelhelm and Dr. Ingo Manke studied the reaction of copper sulfide (a naturally occurring mineral) as the cathode of a solid-state battery, which uses lithium as the anode. One characteristic of batteries is the formation of large copper microcrystals during discharge.

The formation of microcrystals enables detailed investigation of reactions through X-ray tomography. Therefore, researchers can track (discharge) charging reactions in 3D and for the first time, track the movement of cathode particles inside the battery. In addition, research has shown that cracking can be effectively reduced through higher pressure.

The co first authors of this paper, Dr. Zhenggang Zhang and Dr. Kang Dong, explained, "For complex measurements, we had to make some compromises and conduct many reference experiments. However, the results provided detailed information on the internal working principles of solid-state batteries and demonstrated how to improve their performance."

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