In-situ XAS analysis of ionic species in FeCl₂ aqueous solution


We performed X-ray absorption spectroscopy measurements at P65 beamline of PETRA III synchrotron radiation source at DESY, Hamburg in August 2020 within project I-20200036 EC 'In-situ Fe K-edge XAS analysis of ionic species in the highly concentrated FeCl2 aqueous solution for energy storage technology'. In-situ Fe K-edge XANES and EXAFS analysis are aimed at identifying ionic species in FeCl2 aqueous solution at room temperature and the change in their population with the temperature almost up to the boiling point. From the structural data, we will be able to determine the temperature dependence of related dissociation constants.  This study was the first comprehensive experimental study of the ionic structures and their temperature dependence, relevant for  the power-to-solid grid energy storage technology .