Optimization of the surface structure and properties is of great concern in that the failures of engineering materials such as wear, erosion and fatigue usually occur on the surface of materials. Plastic deformation from the sliding friction process has been utilized to realize surface nanocrystallization in commercial pure copper and tantalum plates in this work. The optical microscopy, transmission electron microscopy, X-ray photoelectron spectra, and uniaxial tensile testing results suggested that clean nanocrystalline surface layers of pure copper and tantalum were obtained, significantly strengthening the materials after the treatment.

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Anode‐supported micro‐tubular SOFCs based on a proton and oxide ion mixed conductor electrolyte, BaZr0.1Ce0.7Y0.1Yb0.1O3−δ (BZCYYb), have been successfully fabricated via phase‐inversion process. Typical micro‐tubular cell with the configuration of Ni‐BZCYYb|BZCYYb|La0.6Sr0.4Co0.2Fe0.8O3–δ, consists of anode support, electrolyte and cathode with thicknesses of 200, 12, and 10 μm, respectively. The cells show excellent electrochemical performance with the peak power densities of 1.040, 0.902, 0.721, and 0.590 W cm−2 at 750, 700, 650, and 600 °C, respectively, with humidified (3 vol.% H2O) hydrogen as fuel and ambient air as oxidant. The AC impedance spectroscopy result shows low concentration polarization values of 0.016–0.021 Ω cm2 at 750–600 °C. Further, significant performance enhancement is observed during long‐term stability test at 600 and 750 °C under constant voltage of 0.5 and 0.7 V over 120 h, respectively, indicating excellent stability of BZCYYb under fuel cell operating condition. The high performance is attributed to high‐quality cell, validated by the dense, crack‐free BZCYYb electrolyte film supported by the anode with micro sponge‐like pores.