The results represent a step in the development of new energy storage systems. The use of electricity to generate hydrogen is considered to be a key technology for the storage of surplus energy from renewable sources. It could also play a crucial role in the transition of the energy system and the stabilization of grids.
As a result, Siemens' Industry Sector is developing and producing electrolyzers whose polymer electrolyte membrane (PEM) cells generate hydrogen at high pressure and temperatures under 100 degrees Celsius.
In a project funded by the German Ministry of Economics, scientists at Siemens' global research unit Corporate Technology (CT) have now also investigated high-temperature electrolysis. This technology could be more efficient than the conventional approach, since electrolysis reactions require a much lower cell voltage at high temperatures.
Another interesting property of high-temperature electrolysis is that the flow of the electricity can be reversed, allowing users to switch back and forth between efficient electrolysis processes and fuel cell operation. Such a system could use natural gas, biogas, or hydrogen to generate electricity or produce combined heat and power.
A future high-temperature electrolyzer could also be coupled with a system for synthesizing chemicals such as methane. The resulting waste heat could be used to generate the water vapor needed for high-temperature electrolysis. According to the researchers' simulations, hydrogen generation and methane synthesis would each have an efficiency of about 75 percent relative to their respective calorific values. This already takes into account the compression of the gases to 80 bars.
In the project, the CT researchers worked together with the ceramics manufacturer Kerafol and Forschungszentrum Jülich to optimize electrochemical cells that use an oxygen ion-conducting electrolyte as a substrate. The main challenge was to prevent the oxygen electrode from becoming detached, which had previously caused aging effects.
The researchers improved the electrode's stability by making it from a material that conducts electrons as well as oxygen ions. In a CT lab in Erlangen, ceramic electrolytic cells ran for more than 8,000 hours at 850 degrees Celsius. The cells had a current density of 0.5 amperes per square centimeter and a cell voltage of up to 1.1 volts. In this endurance test, the researchers noticed that the voltage-related aging amounted to only 0.2 percent per 1,000 hours of operation.
The researchers also demonstrated a concept for constructing the cell stacks. However, further development work is needed before larger cell stacks will have a sufficiently high level of long-term stability. The presentation of the lab results at project's sponsor brought the work on the three-year project's technology to a successful conclusion.
Dr. Norbert Aschenbrenner | Siemens InnovationNews
Laser sensor LAH-G1 - optical distance sensors with measurement value display
15.08.2017 | WayCon Positionsmesstechnik GmbH
Engineers find better way to detect nanoparticles
14.08.2017 | Washington University in St. Louis
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
17.08.2017 | Physics and Astronomy
17.08.2017 | Earth Sciences
17.08.2017 | Physics and Astronomy