The second discussion session hosted by Danish Battery Society was held at Center for Materials Crystallography (CMC), Aarhus University.
The topic of the session was the relation between synthesis, structural and electrochemical properties of electrode materials used for battery materials. All talks were given by PhD students and Postdocs in the CMC battery group. A short summary of each talk is found below and the presentations will be included as they are received.
Introduction and TiO2
by Martin Søndergaard
Martin gave a general introduction to the battery group at Aarhus University and described how they take advantage of a closely integrated feedback loop between synthesis, structure characterization and electrochemical properties. The battery test cells used in the group were described, including the in-situ split flat cell used to do in-situ XRD tests.
The second part of the talk described recent progress in synthesis of TiO2 nanoparticles.
Procrystal analysis for easy visualization of Li-pathways
by Mette Filsø
Mette introduced a new method to visualize Li-ion pathways in Li-ion battery intercalation materials. The method is based on the framework Procrystal that calculates the migration barrier for Lithium inside the crystal. The calculation is based on the unit cell dimensions, space group and atomic positions. The method is still not quantitative, but it has succeeded in predicting the Lithium pathways in several common battery materials.
Na-ion batteries and in-operando studies
by Yanbin Shen
Yanbin described the benefits and challenges of working with Na-based materials rather than Li-materials. The Na-ion is bigger than the Li-ion which reduces the anti-site effect. Because of this, many Li-ion materials are actually synthesized using Na-precursors with a subsequent ion-exchange step. Working with Na-ion enables a wider range of cathode materials. In the latter part of the talk, Yanbin pointed out practical tips and tricks to improve cycling and how to handle Na-foil.
by Kirsten M.Ø. Jensen
Kirsten presented one of the core competences of the group, namely measurement and analysis of total scattering. With the methods presented, it is possible to look at local order with X-rays and obtain information on nanocrystalline and amorphous materials and quantification of crystalline phases. Kirsten gave an example, were a co-precipitation synthesis was followed in-situ.
by Troels L. Christiansen
Troels gave a presentation on characterizing the structure of LiMn2O4 nanoparticles and discussed layered vs. Spinel structures.
Solid state electrolytes
by Morten B. Ley
Morten presented his work on LiBH4-like materials as solid state electrolytes. The electrolytes are tested in a catholyte, where the electrolyte is mixed with LiCoO2. Initial experiments showed poor performance and the suggested reason is a non-conducting interface layer between the electrolyte- and cathode material. It was speculated that this effect may be suppressed with an interface layer.
The presenters were thanked for their work and looking forward to the next discussion session the group talked about the next topic and venue. In general, an increased focus on discussion of best practice in testing and characterization was desired and also presentations from some of the visitors would be a good idea in the future to unfold the topics of the sessions in a broader context. AAU would be happy to host a session in 2014, but more info on time, place and topic for the next session will follow. Suggestions are always welcome at firstname.lastname@example.org.
The day ended with a guided tour through the facilities at the Center for Materials Crystallography.
19 September, 10:30 to 16:30. Meeting room 1-512-320, Aarhus University, Langelandsgade 140, 8000 Aarhus C
The relation between synthesis, structural and electrochemical properties of electrode materials is at the core of the research in the battery subgroup at Center for Materials Crystallography, Aarhus University. For several material systems, the electrochemical performance of electrode materials depends strongly on particle size, morphology, structure defects and surface area. These parameters can often be tuned through the synthesis conditions, e.g. in a hydrothermal synthesis by adjusting the temperature, pressure, concentrations, pH and/or addition of surfactants.
Currently, we are seven persons at Center for Materials Crystallography working on different projects related to synthesis, structure and performance studies of materials for Li- and Na-ion batteries. We would like to share our research with the Danish Battery Society and to further open for discussions of topics related to synthesis and characterization of Li- and Na-ion battery electrode materials.
The topics will include: Description of common preparation techniques for electrode materials, in-situ characterization of nanoparticles as they form during a synthesis, calculations of Li-ion pathways, advanced characterization techniques to assess Li-behavior in structures and in-situ characterization of electrode materials during charge and discharge. Presentations of approximately 30 min will be given from various research projects.
During the day a lab tour will be organized to show our facilities for synthesis and structural characterization of materials as well as the battery lab.
The event will start at 10:30 on Thursday the 19th of September and depending on the level of discussion it should end around 16.30.
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