Research Highlights 2016
Highlight 1: Breakthrough on operando techniques for battery research
In 2016 two major breakthroughs on operando techniques have been made: Scientists at FZJ have shown, that at singlet oxygen (1Dg) is formed in an aprotic lithium–oxygen battery upon Li2O2 oxidation at potentials above 3.5 V. Singlet oxygen was detected through a reaction with a spin trap to form a stable radical by time- and voltage resolved operando EPR spectroscopy. The occurrence of highly reactive singlet oxygen might be the long-overlooked missing link in the understanding of the electrolyte degradation and carbon corrosion reactions that occur during the charging of Li–O2 cells. A HZB team - in cooperation with colleagues from TU Clausthal - has directly observed a lithium-silicon half-cell with an unprecedented spatial and temporal resolution during charging and discharging. Using operando neutron reflectometry methods this team was able to precisely track how the lithium ions migrate into the silicon electrode and how fast they are moving. These results pave the way for the technical use of this very promising electrochemical system.
Highlight 2: System for the generation of protective gas for the avoidance of an additional gas supply
In order to avoid the reoxidation of the nickel anode used in the SOFC, a reducing atmosphere is required in all operating phases. Through the combination of dynamic simulation models with experiments, a highly efficient total system consisting of anode exhaust gas recirculation and systemic gassing generation was developed which avoids the necessity of a separate supply with forming gas, an important step towards commercialization. This was achieved through the use of a new recycling rate measuring method, an analysis of the carbon-free operating window, as well as an innovative operating strategy within the protective gas-requiring operating phases.
Highlight 3: Hydrogen fuel cell-based aircraft power train
DLR has demonstrated with partners the world’s first four-seat passenger aircraft (HY4) powered solely by a hybridized hydrogen fuel cell system. DLR developed the aircraft's power train which consists of a hydrogen storage system, a low-temperature hydrogen fuel cell and a high-performance lithium battery which covers peak power loads during take-off and when climbing. With hydrogen generated via electrolysis from renewable electricity the HY4 can fly without generating any emissions at all. On 29 September 2016, the HY4 aircraft took off on its first official flight from Stuttgart Airport.