In-situ Raman spectroscopy analysis of the interfaces between Ni-based SOFC anodes and stabilized zirconia electrolyte

TL;DR

This paper introduces a novel in-situ Raman spectroscopy method using transparent zirconia membranes to analyze Ni-based SOFC anode interfaces, enabling direct observation of electrochemical reactions and kinetics.

Contribution

The study develops and validates a new in-situ Raman spectroscopy technique for analyzing SOFC electrode-electrolyte interfaces with simultaneous electrochemical measurements.

Findings

Excellent agreement with literature on NiO reduction kinetics

Porous cermet reduction follows Avrami model at 400-600°C

Reaction rate limited by Ni diffusion during metal nuclei growth

Abstract

A new experimental approach for in-situ Raman spectroscopy of the electrode | solid electrolyte interfaces in controlled atmospheres, based on the use of optically transparent single-crystal membranes of stabilized cubic zirconia, has been proposed and validated. This technique makes it possible to directly access the electrochemical reaction zone in SOFCs by passing the laser beam through single-crystal electrolyte onto the interface, in combination with simultaneous electrochemical measurements. The case study centered on the analysis of NiO reduction in standard cermet anodes under open-circuit conditions, demonstrated an excellent agreement between the observed kinetic parameters and literature data on nickel oxide. The porous cermet reduction kinetics at 400-600C in flowing H2-N2 gas mixture can be described by the classical Avrami model, suggesting that the reaction rate is determined by the metal nuclei growth limited by Ni diffusion. The advantages and limitations of the new experimental approach were briefly discussed.