Scientists supported by the SNSF have produced novel electrolytes for rechargeable sodium and magnesium batteries. The research group’s objective was to develop alternatives to lithium-ion technology.
A project supported by the Swiss National Science Foundation (SNSF) aims to find new materials which can be used in rechargeable batteries and eventually provide alternatives to the current lithium batteries.
Lithium-based batteries have several drawbacks, such as the limited availability of the raw material itself as well as the numerous safety issues, which are primarily associated with the use of a flammable liquid compound. This problem has been exemplified by the recurrence of exploding mobile phones.
The recent research led by Arndt Remhof of the Swiss Federal Laboratories for Materials Science and Technology, Empa, demonstrates the potential of sodium and magnesium in the development of alternative technologies based exclusively on solid elements. His team has produced experimental battery components based on these metals.
Changing the material
Swiss researchers have developed solid-state battery cells using a solid compound (as opposed to cells which are based on a liquid electrolyte), the design of which poses a significant technical problem. Ions - whether they are lithium, sodium or magnesium - must be allowed to move through a solid medium. By moving from one pole to the other inside the battery, ions (positive charge) facilitate the displacement of electrons (negative charge) and thus the discharge of an electrical current through an external circuit.
To facilitate the displacement of ions, the researchers developed solid electrolytes with crystalline structure. By substituting lithium with sodium or magnesium, Arndt Remhof’s team had to completely overhaul their crystalline architecture and use new components and manufacturing processes.
“I always like to compare our job to that of a football coach”, says Arndt Remhof. “You can bring the best elements together, but if you don’t optimise the settings you won’t achieve good results!”
Sodium: a cheap material
Arndt Remhof’s team has developed a solid electrolyte that facilitates good mobility of sodium ions at 20 degrees. This last point is crucial: ions require a source of heat in order to move, and inducing a reaction at room temperature poses a technical challenge. The electrolyte is also non-flammable and is chemically stable up to 300 degrees, which addresses the various safety concerns associated with lithium-ion batteries.(*) Hans Hagemann’s team at the University of Geneva has been working in parallel to develop cheaper technology for the production of this new solid electrolyte.(**)
Unlike lithium, there are huge reserves of sodium: it’s one of the two components of table salt. “Availability is our key argument”, says Léo Duchêne of Empa and first author of the research paper. “However, it stores less energy than the equivalent mass of lithium and thus could prove to be a good solution if the size of the battery isn’t a factor for its application.”
Magnesium: the perfect but complex material
The same team has also developed a solid magnesium-based electrolyte.(***) Until now, very little research had been done in this field. The fact that it is much more difficult to set this element in motion doesn’t mean that it is any less attractive: it’s available in abundance, it’s light, and there’s no risk of it exploding. But more importantly, a magnesium ion has two positive charges, whereas lithium only has one. Essentially, this means that it stores almost twice as much energy in the same volume.
Some experimental electrolytes have already been used to stimulate magnesium ions to move, but at temperatures in excess of 400 degrees. The electrolytes used by the Swiss scientists have already recorded similar conductivities at 70 degrees. “This is pioneering research and a proof of concept,” says Elsa Roedern of Empa, who led the experiments. “We are still a long way from having a complete and functional prototype, but we have taken the first important step towards achieving our goal.”
The Novel Ionic Conductors project brings together researchers from Empa, the University of Geneva, the Paul Scherrer Institute and the Henryk Niewodniczanski Institute for Nuclear Physics in Poland. It has been funded by the Swiss National Science Foundation since 2015 as part of the Sinergia programme, which supports collaborative and interdisciplinary research. “What we have managed to achieve in less than two years is quite extraordinary!” says Arndt Remhof.
Phone +41 58 765 4369
Project “Novel Ionic Conductors” on the project database of the SNSF http://p3.snf.ch/project-160749
(*) L. Duchêne, R.-S. Kühnel, D. Rentsch, A. Remhof, H. Hagemann and C. Battaglia: A highly stable sodium solid-state electrolyte based on a dodeca/deca-borate equimolar mixture. Chemical Communications (2017) https://doi.org/10.1039/C7CC00794A
(**) R. Moury, A. Gigante, and H. Hagemann. An alternative approach to the synthesis of NaB3H8 and Na2B12H12 for solid electrolyte applications. International Journal of Hydrogen Energy (2017) http://doi.org/10.1016/j.ijhydene.2017.02.044
(***) E. Roedern, R.-S. Kühnel, A. Remhof, C. Battaglia: Magnesium Ethylenediamine Borohydride as Solid-State Electrolyte for Magnesium Batteries. Scientific Report (2017) https://doi.org/10.1038/srep46189
Media - Abteilung Kommunikation | idw - Informationsdienst Wissenschaft
A smart safe rechargeable zinc ion battery based on sol-gel transition electrolytes
20.07.2018 | Science China Press
Future electronic components to be printed like newspapers
20.07.2018 | Purdue University
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
20.07.2018 | Power and Electrical Engineering
20.07.2018 | Information Technology
20.07.2018 | Materials Sciences