Solid Oxide Cells (SOCs) are electrochemical devices typically operated at temperatures of 750-850ºC that directly convert a fuel (typically hydrogen) into electricity (fuel cell mode, SOFC) or electricity into hydrogen (electrolysis mode, SOEC). Nowadays, the State-of-the-Art (SoA) cells consist of a yttria-stabilized zirconia (YSZ) dense electrolyte, a porous fuel electrode of Ni-YSZ cermet, a porous oxygen electrode of Lanthanum Strontium Cobalt Iron (LSCF) and Gadolinium-doped Ceria (GDC) barrier layer sandwiched between the oxygen electrode and the electrolyte to limit their reactivity. In recent years, the interest on SOCs has grown significantly thanks to their wide range of technological applications that could offer innovative solutions for the transition toward a renewable energy market.

In the last decades, numerous strategies for improving the performance and reliability of Solid Oxide Fuel Cells (SOFCs) have been proposed from the macroscopic control of cell design to the enhancements in materials selection for the electrolyte and electrodes. Recently, a new effective strategy has achieved to reduce the electrode polarization of SOFCs enlarging the contact area of electrode-electrolyte interface. In this regard, pulsed laser machining has emerged as an effective method for corrugating the surface of Ni-YSZ anode and YSZ electrolyte in a controlled, flexible, and reproducible way, and therefore, for enlarging the electrode-electrolyte interface. However, laser-material interaction using a nanosecond pulsed laser can involve thermal effects on the surface.

The objective of this work was to analyse the microstructural and phase changes, and the damage caused by laser machining on the sintered NiO-YSZ surface for SoA cells. For this purpose, several laser patterns consisting in parallel tracks on NiO-YSZ surfaces were processed using a nanosecond pulsed laser. Complementary characterization techniques, such as Field Emission Scanning Electron Microscopy (SEM), Raman Spectroscopy, X-Ray Diffraction (XRD), and X-ray Photoelectron Spectroscopy (XPS), were used to analyse the effects of laser treatment on the material composition and microstructure. Finally, the mechanical properties (hardness and elastic modulus) of laser treated surfaces at sub-micrometric scale were determined using Nanoindentation technique.