HZB presents research on thermoelectrics
HZB Group at the ICT/ECT2015. From left to right: Dr. Klaus Habicht (Head of the Department for Methods for Characterization of Transport Phenomena in Energy Materials), Dr. Tommy Hofmann, Dr. Katharina Fritsch, Dr. Britta Willenberg, Dr. Katrin Meier-Kirchner
The annual "International Conference on Thermoelectrics (ICT)” and the "European Conference on Thermoelectrics (ECT)” took place together from 29 June to 02 July 2015 in Dresden, Germany. For the first time, HZB participated in this international multidisciplinary meeting. The HZB Department "Methods for Characterization of Transport Phenomena in Energy Materials" headed by Dr. Klaus Habicht presented their research in two talks and one poster.
Dr. Tommy Hofmann presented a talk on the thermoelectric properties of nanostructured silicon which is prepared at HZB by an electrochemical etching process and which is characterized in-house by macroscopic techniques, and by microscopic probes. This material is currently of great interest as silicon is earth-abundant, non-toxic and inexpensive, which distinguishes it from current thermoelectric materials such as Bi2Te3 or PbTe. The nanostructuring of this simple material offers new possibilities to increase the thermoelectric efficiency of the material, for example by reducing the thermal conductivity through the artificial creation of interfaces within the material. The thermal conductivity as macroscopic quantity relates to the transport of lattice vibrations or phonons on the microscopic level, which can be ideally studied using inelastic neutron scattering techniques available at HZB's research reactor BER II.
In the second talk, Dr. Katharina Fritsch gave an overview of the experimental methods for thermoelectrics research applied in the Department, and she presented selected ongoing research projects. Discussed projects ranged from nanostructured silicon to experiments on the lattice dynamics and electronic bandstructure of low-dimensional thermoelectric single crystals as well as structural investigations of skutterudite compounds.
The structure-functionality relationship in skutterudite compounds were also the topic of the poster entitled "Yb-filled skutterudites: a combined macroscopic and microscopic approach", in which Dr. Britta Willenberg presented results of a project realised as cooperation between the Department and the Institute of Materials Research at the German Aerospace Center (DLR) in Cologne.
The meeting was a perfect venue to get feedback on our research projects and to present the experimental facilities and research opportunities at HZB to a large audience from Germany and abroad. Overall, we we were able to attract new potential collaboration partners.
- Sodium-ion batteries: New storage mechanism for cathode materialsLi-ion and Na-ion batteries operate through a process called intercalation, where ions are stored and exchanged between two chemically different electrodes. In contrast, co-intercalation, a process in which both ions and solvent molecules are stored simultaneously, has traditionally been considered undesirable due to its tendency to cause rapid battery failure. Against this traditional view, an international research team led by Philipp Adelhelm has now demonstrated that co-intercalation can be a reversible and fast process for cathode materials in Na-ion batteries. The approach of jointly storing ions and solvents in cathode materials provides a new handle for the designing batteries with high efficiency and fast charging capabilities. The results are published in Nature Materials.
- New Helmholtz Young Investigator Group at HZB on perovskite solar cellsSilvia Mariotti starts building up the new Helmholtz Young Investigator Group ‘Perovskite-based multi-junction solar cells’. The perovskite expert, who was previously based at Okinawa University in Japan, aims to advance the development of multi-junction solar cells made from different perovskite layers.
- Hydrogen storage in MXene: It all depends on diffusion processesTwo-dimensional (2D) materials such as MXene are of great interest for hydrogen storage. An expert from HZB has investigated the diffusion of hydrogen in MXene using density functional theory. This modelling provides valuable insights into the key diffusion mechanisms and hydrogen's interaction with Ti₃C₂ MXene, offering a solid foundation for further experimental research.