Evonik Research Prize for lithium-ion battery test cell with separated electrodes
For years, small rechargeable lithium-ion batteries have reliably supplied billions of portable devices with energy. But manufacturers of high-energy applications such as electric cars and power storage systems seek for new electrode materials and electrolytes. Michael Metzger, researcher at the Technical University of Munich (TUM), has now developed a new battery test cell allowing to investigate anionic and cationic reactions separately. Recently the researcher was honored with the Evonik Research Prize for his work.
Michael Metzger, researcher at the Technical University of Munich (TUM), shows the core of his new battery test cell: A glass ceramic membrane, coated with aluminum and plastic, allows only lithium ions to pass through. It is impermeable to all other components of the electrolyte fluid, thus allowing to investigate anionic and cationic reactions in lithium-ion batteries separately.
Credit: Monika Weiner / TUM
Energy storage systems are in demand as never before. Billions of mobile telephones and tablets need electricity to go. Add to this the growing number of electric cars. But, high-performance batteries can also store renewable energy produced by wind turbines and solar cells so that it can be fed into the grid on cloudy and windless days.
"Manufacturers of rechargeable batteries are building on the proven lithium-ion technology, which has been deployed in mobile devices like laptops and cell phones for many years," reports TUM researcher Michael Metzger. "However, the challenge of adapting this technology to the demands of electromobility and stationary electric power storage is not trivial."
Standard rechargeable batteries are only marginally suited for high performance: "To raise the energy density, you need to increase the voltage or the capacity, and that is where traditional electrode materials and electrolytic fluids reach their limits," explains the physicist.
Research is thus running at full pace around the world. For example, engineers are experimenting with special electrode materials that can provide a voltage of nearly 5 volts, instead of the current maximum of 4.2 to 4.3 volts.
Consult your engineer about risks and side-effects
But this "battery doping" also has side-effects. Changes in the chemical composition of the electrodes and electrolytes can lead to battery performance drops after only a few charging cycles or the formation of gasses at the electrodes that cause the batteries to balloon.
"The future of lithium-ion batteries hinges on getting a grip on these undesirable reactions," predicts Metzger. He has already fulfilled one prerequisite to this end: The chemical processes that transpire during charging and discharging can be investigated in detail using the new battery test cell he developed with his team.
A test cell for the batteries of the future
The researchers spent three years working on their apparatus. "Normally electrolytic fluids and electrodes - the positive cathode and negative anode - are in a permanent electrochemical exchange," says Metzger. "Thus far it has not been possible to investigate the reactions at the anode and cathode independently of each other. We are the first to manage this successfully."
The key: The battery test cell, which, like every lithium-ion battery, comprises an anode, a cathode and electrolytes is not completely sealed, but rather is fitted with a fine capillary. This allows gasses that are released during charging and discharging to be sampled and investigated using a mass spectrometer.
To study the processes at anodes and cathodes independently of each other, the engineers also modified the membrane - a thin glass ceramic platelet coated with aluminum and synthetics - to make it permeable not only by lithium ions, but also by all other components of the electrolytic fluid.
Water is poison for a battery
Using their test cell, the researchers were, for the first time, able to explain precisely what transpires inside a high-voltage battery. The results demonstrate that the stability of electrodes and electrolytes depends on several factors, for example, charging voltage, operating temperature and even tiniest chemical impurities:
Measurement in practice
"For industrial end-users, the new measurement methodology is extremely interesting," says Prof. Hubert Gasteiger, who chairs the Department of Technical Electrochemistry. "In our investigations, we were able to show that the development of gasses in batteries can be reduced by adding the right admixtures to the electrolytic fluid or by inhibiting crosstalk between the electrodes."
One research result, in particular, bears a direct consequence in practice: The higher the desired voltage, the less residual moisture the materials may contain. Manufacturers could extend the lifetime of future cells by replacing the electrolyte ethylene carbonate with more stable solution components.
But here to the devil is in the detail: A small amount of ethylene carbonate is required in current systems to pacify the anode. The new cell allows processes at the anode and the cathode to be observed independently, possibly leading to the discovery of entirely novel solutions.
Evonic Research Prize for innovative developments
Metzger was recently honored with the Evonik Research Prize for the development of the battery test cell, which, for the first time, allows mass spectroscopy investigations and an independent analysis of the processes at each electrode. The chemical group Evonik awards the prize annually to an exceptional next-generation scientist.
M. Metzger, P. Walke, B. Strehle, S. Solchenbach, and H. A. Gasteiger: Anodic Oxidation of Carbon and Electrolyte with Different Conducting Salts in High-Voltage Lithium-Ion Batteries Studied By Online Electrochemical Mass Spectrometry; Pacific Rim Meeting on Electrochemical and Solid-State Science, 5. Okt. 2016
M. Metzger, B. Strehle, S. Solchenbach, and H. A. Gasteiger: Hydrolysis of Ethylene Carbonate with Water and Hydroxide under Battery Operating Conditions, J. Electrochem. Soc., 163 (7), A1219-A1225 (2016), DOI: 10.1149/2.0411607jes
M. Metzger, B. Strehle, S. Solchenbach, and H. A. Gasteiger, "Origin of H2-Evolution in LIBs: H2O Reduction vs. Electrolyte Oxidation", J. Electrochem. Soc., 163 (5), A798-A809 (2016), DOI: 10.1149/2.1151605jes
Dr. Andreas Battenberg | EurekAlert!
System draws power from daily temperature swings
16.02.2018 | Massachusetts Institute of Technology
Researchers at Kiel University develop extremely sensitive sensor system for magnetic fields
15.02.2018 | Christian-Albrechts-Universität zu Kiel
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.
But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...
Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.
The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...
Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters
Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...
Let’s say the armrest is broken in your vintage car. As things stand, you would need a lot of luck and persistence to find the right spare part. But in the world of Industrie 4.0 and production with batch sizes of one, you can simply scan the armrest and print it out. This is made possible by the first ever 3D scanner capable of working autonomously and in real time. The autonomous scanning system will be on display at the Hannover Messe Preview on February 6 and at the Hannover Messe proper from April 23 to 27, 2018 (Hall 6, Booth A30).
Part of the charm of vintage cars is that they stopped making them long ago, so it is special when you do see one out on the roads. If something breaks or...
15.02.2018 | Event News
13.02.2018 | Event News
12.02.2018 | Event News
16.02.2018 | Information Technology
16.02.2018 | Health and Medicine
16.02.2018 | Physics and Astronomy