The HIU research group led by Axel Groß has made it on the back cover of the journal Energy & Environmental Science of the Royal Society of Chemistry with its element-specific theory – why battery electrode materials differ in their propensity for growing dendrites. Burning mobile phones or electric cars bursting into flames are caused by the formation of dendrites in batteries. The results could help solve the safety problems with the shrub-like crystal structures that can cause short circuits.
The researchers looked for battery materials that do not form any dendrites at all. While lithium, zinc and sodium batteries often form these spark-inducing structures, magnesium and aluminum batteries are virtually dendrite-free. In order to better understand dendrite formation, they therefore looked for a connection between the self-diffusion barriers of different metals. These barriers are the interfaces that reduce the diffusion of an atom on a surface of the same element and determine how likely it is that metal atoms deposit on electrodes and cause dendrite growth.
By studying the different metals, Axel Groß and his team found that lithium ions have relatively high self-diffusion interfaces, which means that once they have diffused a gradient onto a surface, the lithium ions remain there and form a rough area. The dendrite then branches from this defect. This suggests that dendrite formation is an inherent property of this element. In comparison, metals such as magnesium have a very low self-diffusion barriers and form smooth surfaces, so dendrites occur much less frequently.
The theory was also discussed in a separate news item in Chemistry World:
https://www.chemistryworld.com/news/diffusion-barrier-data-to-help-batteries-ditch-the-dendrites/3009502.article
For more information: pubs.rsc.org/en/Content/ArticleLanding/2018/EE/C8EE01448E
The Analysis of the CO2 footprint and life‐cycle costs of different batteries for stationary applications by scientists from HIU and the Institute for Technology Assessment and Systems Analysis (ITAS), published in “Energy Technology”, has been named one of the journal’s best articles of the year 2017.
The article CO2 Footprint and Life‐Cycle Costs of Electrochemical Energy Storage for Stationary Grid Applications determines life-cycle costs and greenhouse gas emissions of different battery technologies within stationary applications. It is part of the special issue “Energy Research at Karlsruhe Institute of Technology”.
The authors use an innovative combination of life cycle assessment, uncertainty simulation and battery size optimization. In contrast to previous works, they apply dynamic load profiles for the optimization of the size and lifetime of batteries and consider the potential influence of future technology developments like changing electricity mix or battery price decreases. Lithium-Ion batteries are found to be among the most promising battery technologies, due to their high performance and comparatively long lifetime. Classic lead-acid batteries, although cheap on the first glimpse, are less recommendable for stationary applications due to their low lifetime and efficiency.
Which electrolyte is best suited for magnesium batteries to prevent rapid aging and dendrite formation? How can the substrate be optimized to absorb the active material? How can the processes in magnesium batteries be better understood through modelling?
Around 100 scientists from different countries are currently investigating these questions in Ulm. They take part in the 2nd International Symposium on Magnesium Batteries from 27th to 28th September at the Maritim Hotel Ulm. After 2016, the HIU is organising the Symposium on Magnesium Batteries for the second time.
The aim of the symposium is to discuss the current state of research and to present future scenarios. The 24 lectures and even more posters of the symposium deal with the topics electrolytes and additives, electrode interfaces, cathodes, anodes, modelling and systems.
Compared to lithium, magnesium can release and absorb two electrons each, making it a very interesting material for battery research. Magnesium batteries represent a lithium-free alternative in the field of “high-voltage batteries”. The advantages are obvious: magnesium is less reactive and therefore less dangerous. With magnesium, fewer dendrites are formed during charging, which are the main safety challenge when lithium metal anodes are used. It is also cheaper to manufacture because it reacts less quickly with air than lithium metal and can therefore be processed more easily. Magnesium is more sustainable than conventional battery materials and is present in large quantities, for example in the form of rock dolomite, which results in lower prices. Magnesium batteries could also act as stationary energy storage devices, for example in wind power plants or solar fields.
The Karlsruhe Institute of Technology (KIT), the Ulm University, the Centre for Solar Energy and Hydrogen Research Baden-Württemberg (ZSW) and the University of Giessen have successfully acquired the Cluster of Excellence “Energy Storage Beyond Lithium – New Storage Concepts for a Sustainable Future” within the Excellence Strategy of the Federal Government and the States. Part of the seven-year funding of up to 10 million euros per year will also benefit the HIU as a joint institute of KIT and the Ulm University. The cluster decision was announced in Bonn on 27 September 2018 by Anja Karliczek, Federal Minister of Education and Research and Chairwoman of the Joint Science Conference (GWK), and Professor Eva Quante-Brandt, Bremen’s Senator of Science and Deputy Chairwoman of the GWK.
At the heart of the approved Cluster of Excellence is research into high-performance, reliable and environmentally friendly storage systems for energy system transformation and electromobility. The researchers will develop a fundamental understanding of electrochemical energy storage in novel systems, combine basic material properties with critical performance parameters and thus lay the foundations for the commercial use of post-lithium technologies. Conventional lithium-ion batteries have almost reached their maximum storage capacity. In order to make progress in performance, the development of new, alternative storage materials and concepts must also be advanced. Another significant leap in the energy density of battery cells requires new electrochemical pairings. For this reason, electrochemists, materials scientists and modellers are looking for alternative charge carriers in the approved cluster – for example on the basis of sodium, magnesium, aluminium or zinc.
“In the run-up to the cluster decision, the Ulm and Karlsruhe sites decided to cooperate more closely in the field of electrochemical storage: The researchers have jointly founded CELEST, the Center for Electrochemical Energy Storage, one of the world’s largest research alliances for energy storage. Thanks to the Cluster of Excellence with around 100 additional employees, the consortium is growing even further,” explained Maximilian Fichtner, Director of the HIU and spokesman for the Cluster of Excellence.
The Excellence Strategy is intended to strengthen Germany as a research location and increase the international competitiveness of universities. Starting this year, the Federal Government and the Länder will provide 533 million euros per year for these goals. In the “Clusters of Excellence” funding line, 40 German universities submitted 88 applications, 57 of which the Excellence Commission has now selected for funding. In total, around 385 million euros are available annually for this funding line. Clusters of Exzellence can be funded with three to ten million euros annually, initially for seven years. Funding will begin on 1 January 2019 and a second funding period of seven years will be possible from 2026.
On October 1, the management of the Institute changed. Prof. Stefano Passerini takes over the position of Director and the former Director Prof. Maximilian Fichtner becomes his deputy. According to the statutes, a rotation is scheduled every three years. Three years ago, Prof. Fichtner replaced the founding director Prof. Horst Hahn.
“In the few years since its inception, HIU has reached an outstanding level in Germany, as demonstrated by the top ranking within the Helmholtz Association and the leading role that it plays in the recently granted Post-Lib project funded within the national Excellence Initiative, as well as world-wide, as testified by the great number of high-quality scientific publications, the participation in several international bi- and multilateral research project and the establishment of Memorandum of Understanding with top-level laboratories such as the Argonne National Laboratory in the USA”, said Stefano Passerini. The establishment of two Young Investigator Research Groups further shows the vitality of the Institute towards the future development. As a result of such vivid development, the Institute has already reached his full occupancy in terms of available laboratory and office space, in spite of its rather recent inauguration in late 2014. Thus, I hope that the HIU founding partners (KIT, UniUlm, DLR and ZSW) will soon enable the Institute to further expand in the near future, he explained.
Stefano Passerini has been a professor at the HIU since January 2014 and heads the largest research group at the institute. He has been working on the development of materials and systems for electrochemical energy storage for 30 years. His research focuses on the basic understanding and development of materials for lithium batteries, such as ionic liquids, polymer electrolytes and electrode materials. Passerini is the co-author of over 500 publications and for the third year in a row one of the most cited researchers in his field. In addition, several newly developed materials have already been patented.
“I would like to thank you for the great collaboration that has been so fruitful in recent years and let me express my sincere wishes that we keep on going on this road of success,” said Fichtner during the handover. During his term, he approved the Cluster of Excellence “Energy Storage Beyond Lithium – New Storage Concepts for a Sustainable Future”, in which he is spokesman and in which HIU participates via the Karlsruhe Institute of Technology (KIT). At the same time, he played a key role in founding CELEST, the Center for Electrochemical Energy Storage, one of the world’s largest research alliances for energy storage, which he also heads as director.
Five professors who lead a research group at the HIU presented their research, thesis topics and career paths at the HIU during the “Long Night of Chemistry”. The event was organised for the third time by the Chemistry Student Council of the Ulm University. Around 90 bachelor students from the fifth semester of chemistry, economic chemistry and chemical engineering were informed about their possible future paths.
The HIU sees it as one of its core tasks to offer young academics ideal framework conditions. The Institute’s promising and international environment provides interested students and doctoral candidates a variety of opportunities to gain qualifications with student research projects, bachelor’s and master’s theses and doctorates. In addition to the often theoretical studies at universities, the HIU offers students with a scientific-technical orientation the opportunity to acquire practical experience.
Prof. William S. Price from Western Sydney University gave a lecture at the HIU Seminar on „Performing Accurate NMR Diffusion Measurements of Electrolytes“. He is known internationally for his work on magnetic resonance techniques for measuring molecular dynamics. His research interests include Biological and Medical Physics, Magnetic Resonance, and Physical Chemistry: Especially molecular dynamics in biological (e.g., tumours, plants) and chemical systems using NMR imaging (i.e., MRI), relaxation and NMR measurements of translational diffusion, and MRI contrast agents. His research has direct applications to a wide range of practical problems including cancer treatment, pharmaceutical screening and electrolyte systems. Price has published one book, 26 book chapters and 156 journal publications. Besides he is President of the Australian and New Zealand Society for Magnetic Resonance.
Rechargeable magnesium batteries are one of the most promising candidates for the next generation of batteries. Despite recent advances in development, the slow transport of double-charged magnesium ions in storage materials poses one of the greatest challenges in the realization of rechargeable magnesium batteries.
An important breakthrough has now been achieved to overcome the sluggish kinetics in the magnesium battery caused by the strong interaction between the double-charged magnesium ions and the intercalation host. In layered molybdenum disulfide structures, for example, the intercalation kinetics could be significantly increased by using solvated magnesium ions ([Mg(DME)x]2+). The HIU study demonstrates that the high charge density of magnesium ion may be mitigated through dimethoxyethane solvation. This facilitates magnesium ion diffusion.
It is possible that this concept can also be extended to other host structures. This would significantly advance the development of magnesium batteries.
For the third time in a row, Clarivate Analytics has honored Stefano Passerini as a “Highly Cited Researcher” in the Web of Science. His research is once again among the first one percent of the most cited work in his field of research and thus has a special influence on battery research.
Stefano Passerini has been a professor at the HIU since January 2014 and is director of the institute since 2018. He has been working on the development of materials and systems for electrochemical energy storage for 30 years. His research focuses on the basic understanding and development of materials for lithium batteries, such as ionic liquids, polymer electrolytes and electrode materials. Passerini is the co-author of over 500 publications and for the third year in a row one of the most cited researchers in his field. In addition, several newly developed materials have already been patented.
From 23 to 25 January 2019, the Kompetenznetzwerk Lithium-Ionen-Batterien (KLiB) organized the Batterieforum Deutschland with the support of the Federal Ministry of Education and Research (BMBF). For the seventh time already, the interdisciplinary and cross-sector scientific-technical congress brought together scientists from university and non-university research institutions, industry and politicians to develop an interdisciplinary understanding of batteries through dialogue.
On the first day, invited speakers from industry, science and politics looked at the topic of batteries in Germany from different perspectives. On the following two days, current scientific and technical focal points were discussed. Prof. Maximilian Fichtner, Vice Director of the HIU, moderated the topic block “Raw materials – availability and market scenarios”. Dr. Timo Danner from the Electrochemical Multiphysics Modelling Group presented his results on the production and simulation of high-capacity, structured electrodes and Dr. Marcel Weil, Group Leader of Resources, Recycling, Environment & Sustainability, outlined scenarios for resource requirements for energy storage until 2050.