Tomography shows high potential of copper sulphide solid-state batteries
3D reconstruction of the formation of a copper crystallite in a copper sulfide particle (CuS) during the discharge of a lithium CuS solid-state battery. The volume expansion can lead to the formation of cracks (blue). © K. Dong / HZB
Solid-state batteries enable even higher energy densities than lithium-ion batteries with high safety. A team led by Prof. Philipp Adelhelm and Dr. Ingo Manke succeeded in observing a solid-state battery during charging and discharging and creating high-resolution 3D images. This showed that cracking can be effectively reduced through higher pressure.
Solid-state batteries (SSBs) are currently regarded as a promising battery technology of the future. Compared to the current lithium-ion batteries, which are used in mobile phones, laptops and electric vehicles, SSBs could achieve even higher energy densities and better safety. In addition to research institutes, all major automotive companies are therefore also researching this technology. The main feature of the technology is that the highly flammable liquid electrolytes of lithium-ion batteries are replaced by a solid. The entire battery is therefore consists of only "solid materials", hence the name solid-state battery. In order to produce such a battery, different materials (anode, cathode and electrolyte) must be pressed together under high pressure.
Researchers from the Helmholtz-Zentrum Berlin and Hereon, Humboldt-Universität zu Berlin and the Federal Institute for Materials Research and Testing have now succeeded in observing the processes within such a solid-state battery during charging and discharging. The team led by Prof. Philipp Adelhelm and Dr. Ingo Manke investigated the behavior of copper sulfide, a naturally occurring mineral, as a cathode in a solid-state battery. Lithium was used as anode. A special feature of the battery is that large copper crystallites form during discharge. The formation of large crystallites enables a detailed investigation of the reaction by means of X-ray tomography. Thus, the (dis)charge reaction could be traced in 3D and for the first time the movement of the cathode particles within the battery could be tracked. In addition, it was shown that cracking can be effectively reduced by higher pressure. "For the complex measurements, we had to make some compromises and carry out many reference experiments," explains Dr. Zhenggang Zhang and Dr. Kang Dong, the joint first authors of the publication. "However, the results provide detailed insights into the inner workings of a solid-state battery and show how its properties can be improved."
Note:
The project was funded by the German Federal Ministry of Education and Research (NASEBER and KAROFEST projects) and the China Scholarship Council. At Helmholtz-Zentrum Berlin, research into solid-state batteries using tomography will soon be further expanded. For example, the Federal Ministry of Education and Research is funding the construction of a new tomography laboratory (TomoFestBattLab) with 1.86 million euros.
- Battery research: visualisation of aging processes operandoLithium button cells with electrodes made of nickel-manganese-cobalt oxides (NMC) are very powerful. Unfortunately, their capacity decreases over time. Now, for the first time, a team has used a non-destructive method to observe how the elemental composition of the individual layers in a button cell changes during charging cycles. The study, now published in the journal Small, involved teams from the Physikalisch-Technische Bundesanstalt (PTB), the University of Münster, researchers from the SyncLab research group at HZB and the BLiX laboratory at the Technical University of Berlin. Measurements were carried out in the BLiX laboratory and at the BESSY II synchrotron radiation source.
- New instrument at BESSY II: The OÆSE endstation in EMILA new instrument is now available at BESSY II for investigating catalyst materials, battery electrodes and other energy devices under operating conditions: the Operando Absorption and Emission Spectroscopy on EMIL (OÆSE) endstation in the Energy Materials In-situ Laboratory Berlin (EMIL). A team led by Raul Garcia-Diez and Marcus Bär showcases the instrument’s capabilities via a proof-of-concept study on electrodeposited copper.
- Green hydrogen: A cage structured material transforms into a performant catalystClathrates are characterised by a complex cage structure that provides space for guest ions too. Now, for the first time, a team has investigated the suitability of clathrates as catalysts for electrolytic hydrogen production with impressive results: the clathrate sample was even more efficient and robust than currently used nickel-based catalysts. They also found a reason for this enhanced performance. Measurements at BESSY II showed that the clathrates undergo structural changes during the catalytic reaction: the three-dimensional cage structure decays into ultra-thin nanosheets that allow maximum contact with active catalytic centres. The study has been published in the journal ‘Angewandte Chemie’.