(Invited) In Situ/Operando Investigations of Energy Materials with Soft and Hard X-Ray Spectroscopy

Abstract

Energy issues have become globally important public concerns, and low-carbon green energy will play a key role in the near future. To decrease global greenhouse gas emissions in response to globalization and increasingly stringent carbon emission policies, it is necessary to establish green energy technologies. It has always been a great challenge to boost the energy conversion/generation/storage efficiency of current energy materials. Understanding and controlling the interfacial electronic properties in energy conversion/storage materials requires in-situ/operando characterization tools, of which synchrotron x-ray spectroscopy has many unique features. X-ray absorption spectroscopy is capable to probe the local unoccupied electronic structure (conduction band) while x-ray emission spectroscopy is able to probe the occupied electronic structure (valence band). The addition of resonant inelastic x-ray scattering determines the inter- or intra-electric transitions (d-d, f-f excitation or electron transfer excitation) that reflect the chemical and physical properties. With in situ/operando approach, the way to track the modification of atomic and electronic structures of the energy material under operational environment now becomes accessible. This presentation will report the current achievements and perspectives of in situ/operando synchrotron x-ray spectroscopy, including soft- and hard-x-ray absorption spectroscopy, on energy relevant materials.