Zip folder containing datasets for all measurements in manuscript and supplementary information, organised by figure number.

Data for TGA measurements (Figs. 3 and 4, Figs. S9-12) are arranged in tabular text files, with columns corresponding to time, sample temperature, TGA cell temperature, and sample mass in milligrams. A separate table below the main data includes DSC heatflow measurements, but these are not reported in the main manuscript or SI.

Data for Fig. 5 consist of processed TGA measurements, with equilibrium sample composition at various temperatures and partial pressures arranged in a table (.csv file format).

Data for Fig. 6 and Fig. 7, and Figs. S18-19 consist of a table of pO2 sensor output (units: atm) as a function of time for 7 measured temperatures, for each sample (.csv file format).

Data for Figs. 8 and 9., and Fig. S17 are MATLAB .mat data files, containing the variables 'fit_mat' (corresponding to individual 1/T and k points), 'SFO_k_int_vals', corresponding to the average value of k at each inverse temperature point, 'f_SFOint' and 'gof_SFOint' corresponding to the fitted curves and goodness of fit parameters, and 'E_a' and 'lnA' corresponding to the fitted activation energies and pre-exponential factors, with 95% confidence bands in each fitted parameter.

Data for Figs. S1-3 are Excel workbooks corresponding to XRD measurements and fitted reference phases, arranged by columns as 2theta angle, measured intensity, total fitted intensity, difference between measured and fitted intensity, fitted background, and individual fitted phases as reported in the paper SI

Data for Fig. S13 consist of reported values in literature for SrFeO3 composition as a function of temperature and pO2, with corresponding references given (.xlsx format).

Data for Fig. S14 are composed of estimated values of Thiele modulus for measurements of oxygen release and uptake from each sample at each temperature investigated, arranged in tabular format (.csv file format).

Data for Fig. S15 are estimated values of the dimensionless group kRTL/v for each set of measurements of oxygen release, arranged in tabular format (.xslx file format).

Data for Fig. S16 are values of maximum rate of reaction for each sample during reduction or oxidation in the packed bed reactor (umol/(g s)), with associated standard deviation over repeated cycles.