Methods for operando coherent X‐ray diffraction of battery materials at the Advanced Photon Source

Bragg coherent X‐ray diffraction imaging has become valuable for visualization of the structural, morphological and strain evolution of crystals in operando electrode materials. As the electrode material particles (either in a single‐crystal form or an aggregation form of single crystals) are evenly dispersed and randomly oriented in the electrode laminate, the submicrometer‐sized coherentX‐ray beam can be used to probe the local properties of electrode material crystals using two approaches. Coherent multi‐crystal diffraction provides collective structural information of phase transitions in tens of crystals simultaneously as well as the individual behavior from single crystals, which are oriented at the Bragg condition in the X‐ray illumination volume. Bragg coherent diffractive imaging enables one to monitor the evolution of the morphology and strain in individual crystals. This work explores and highlights the Bragg coherent X‐ray diffraction measurements of battery electrode materials in operando conditions at the 34‐ID‐C beamline at the Advanced Photon Source. The experiment is demonstrated with NaNi1/3Fe1/3Mn1/3O2, a sodium‐ion cathode material loaded in a half cell. The paper will discuss, in detail, the beamline setup, sample mounting and handling, alignment strategies and the data acquisition protocols. Bragg coherent X‐ray diffraction measurements and the associated phase retrieval in order to image cathode materials under operando conditions are described in detail. Experiments with a sodium‐ion cathode material at the 34‐ID‐C beamline at the Advance Photon Source are demonstrated.