Structural Characterization of Yb0.15CMO Oxygen Electrode Material, Oxygen Vacancies, Electronic Localization Changes, and Electrochemical Test Dataset

(1) The crystal structure was characterized using an X-ray diffractometer (XRD; D8 Advance, Bruker) with a Cu Kα radiation source, scanning from 10° to 90° at a step size of 0.02° to obtain the sample structure information. (2) An appropriate amount of Yb0.15CMO powder sample was pressed into a pellet with a diameter of 15 mm, and in-situ high-temperature measurements from room temperature to 700°C were conducted using a high-temperature cell at the 15U beamline station of the Shanghai Synchrotron Radiation Facility (SSRF). (3) A 12 mg powder sample and 38 mg ethyl cellulose were pressed into a circular disc with a diameter of 13 mm. The spectra were measured in transmission mode at room temperature. To ensure accurate determination of the absorption edge, a reference standard sample (MnO) was used for energy calibration. The X-ray absorption fine structure (XAFS) measurements of the Mn K-edge were performed using an X-ray absorption spectrometer (Super XAFS H-3000) and at the 20U2 beamline station of the Shanghai Synchrotron Radiation Facility (SSRF). The collected XAFS data were processed using the Demeter software package; specifically, the atomic background was subtracted by applying a quadratic spline fitting to the k³-weighted absorption spectrum, thereby extracting the EXAFS signal. Subsequently, the χ(k) function was subjected to Fourier transform analysis within the k-value range of 2–10 Å⁻¹ using a Hanning window function to minimize truncation artifacts. The resulting radial distribution function in R-space indicated that the coordination shells were located within the range of 1.6–3.0 Å, corresponding to the first coordination shell atomic interactions around the absorption center. (4) The Mn-L and O-K absorption edges were measured in transmission mode using a laboratory X-ray absorption spectrometer. At the TPS 45A beamline station of the National Synchrotron Radiation Research Center (Hsinchu), the X-ray absorption spectra (XAS) of the Mn-L3 absorption edge were measured in TEY mode with a 1×2 μm beam spot size. (5) The valence states of elements in the samples were determined using an X-ray photoelectron spectrometer (XPS; Thermo Scientific K-Alpha). The oxygen vacancies in the samples were measured using electron paramagnetic resonance (EPR; Bruker A300, Germany)(6) The electrochemical workstation PGSTAT302N (Metrohm Autolab) was used to measure electrochemical impedance spectroscopy (EIS), current-voltage-power density (I-V-P), and stability. The frequency range for EIS data acquisition was 10⁶ to 10⁻¹ Hz, with an amplitude of 10 mV. Battery testing employed wet hydrogen gas. For electrochemical tests, steam was generated using a steam generator (Frantech FD-PE constant flow dual injection pump) at a flow rate of 200 μL/min, and current density was recorded at 1.3V when voltage changes occurred.(7) Take 0.6 g of the powder sample, compress it into a block using a mold, and calcine it at 1200°C for 3 hours. The conductivity measurement is performed within the temperature range of 550-850°C using the four-probe DC method, with the electrochemical workstation (Autolab 302 N) as the testing platform to measure the conductivity