Operando studies into the NiFe battery
The nickel-iron(NiFe)-battery is an old battery technology that has become more relevant again due to the increasing importance of energy storage. Diversification of the battery technologies available is important for two reasons. Firstly, Each battery technology has its strengths and weaknesses. Secondly, the availability of resources varies with the different abundance of each of the chemical elements. For that second reason the NiFe-battery is interesting, especially because iron is widely available. The battery still faces challenges though. Self-discharge, the Hydrogen Evolution Reaction(HER) and the passivation of the electrodes need to be tackled in order to improve performance and make it more competitive.
To this end, Winfried de Haas studied the reaction products that are formed during the charge and discharge of the battery, as well as the influence these products might have on the battery performance. He investigated two additives that can improve the batteries performance: K2SnO3 and FeS. In this thesis, De Haas focused on operando measurements, which means that while the battery is charging or discharging, he applied measurements like spectroscopy and X-ray diffraction. The results from these experiments provided insight into how materials react and move through the battery.