A novel concept for in situ gas-phase laser Raman spectroscopy for solid oxide fuel cell research

Abstract

A planar solid oxide fuel cell (SOFC) operated with hydrogen at T=1123 K was equipped with an optically transparent anode flow field to apply species concentration measurements by 1D laser Raman scattering. The flow channels had a cross section of 3 mm × 4 mm and a length of 40 mm. The beam from a pulsed high-power frequency-doubled Nd:YAG laser (λ=532 nm) was directed through one channel and the Raman scattered light from different molecular species was imaged onto an intensified CCD camera. The main goal of the study was an assessment of the potential of this experimental configuration for a quantitative determination of local gas concentrations. The paper describes the configuration of the optically accessible SOFC, the laser system and optical setup for 1D Raman spectroscopy as well as the challenges associated with the measurements. Important aspects like laser pulse shaping, signal background and signal quality are addressed. Examples of measured species concentration profiles are presented.

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

“…Although microscopic mechanisms of the electrode reactions can be evaluated by well-known electrochemical methods, the resultant information is usually cumulative, except for the microelectrode techniques. One important complementary technique enabling real-time analysis of the SOFC reactions is the Raman spectroscopy, successfully applied for a variety of model systems, processes and fuel cell materials [4][5][6][7][8][9][10][11][12][13]. Due to low penetration depth of the excitation radiation, however, most approaches known in the literature (e.g., [5][6][7][8][9][10][11][12][13]) are mainly based on the Raman spectra collected from the outer boundaries of model electrochemical cells, primarily surfaces of the electrodes and solid electrolyte membranes.…”

“…One important complementary technique enabling real-time analysis of the SOFC reactions is the Raman spectroscopy, successfully applied for a variety of model systems, processes and fuel cell materials [4][5][6][7][8][9][10][11][12][13]. Due to low penetration depth of the excitation radiation, however, most approaches known in the literature (e.g., [5][6][7][8][9][10][11][12][13]) are mainly based on the Raman spectra collected from the outer boundaries of model electrochemical cells, primarily surfaces of the electrodes and solid electrolyte membranes. The electrochemical reaction zones where the majority of ionic and electronic charge carriers are generated, such as the area in vicinity of the triple-phase boundary (TPB), can hardly be achieved to a sufficient extent by viewing the surfaces and edges of the electrode systems.…”

Temperature and gas concentration measurements with vibrational ultra‐broadband two‐beam femtosecond/picosecond coherent anti‐Stokes Raman scattering and spontaneous Raman scattering

“…Spontaneous Raman scattering is one of the standard techniques for this purpose, but it also has some drawbacks. For example, low signal intensities require high laser pulse energies with the risk of damage to optical components, or of plasma generation in the focal zone . For minor species (≲0.1%) detection, usually signal‐enhancement methods such as optical resonators and hollow‐core photonic crystal fibers have to be applied .…”

In SituMeasured Spatial Temperature Variations for Improving Reliability of Numerical SOFC Tools

“…The high operation temperature (773-1273 K) of SOFCs makes the spatial characterization more difficult. Vibrational Raman Spectroscopy (12) and IR Thermography (13) can be employed for diagnosing the spatial concentration and temperature, respectively; however, both of them are quite expensive and they require replacement of the gas distribution plates by transparent components. Although the segmentation method is easy to implement on tubular-SOFCs (3,7,11,14,15), it is quite laborious to apply on planar-SOFCs (2).…”