Efficient conversion of energy between sunlight, chemical bonds, and electricity is crucial towards a closed-loop energy cycle. We have applied synchrotron-based Xray spectroscopy and microscopy techniques to investigate the conversion of electricity to and from chemical bonds in fuel cells, electrolyzers, and intercalation batteries. Using these techniques, we have tracked the motions from electrons, oxygen ions, and lithium ions at interfaces and in the bulk of electrochemically-active materials. New insights in gas-solid surface electrochemistry, and solid-solid phase transformation are guiding the development of better materials for a wide range of energy conversion and storage devices. 電化學工作站(7MHz交流阻抗測試)