The Composite La_2-xNd_xCe₂O_7-δ Material for New Energy Conversion Devices: A Physiochemical and Electrochemical Study

Abstract

In this study, the composite La 2-x Nd x Ce 2 O 7-δ with different concentrations of La 3+ and Nd 3+ in ceria is prepared through the sol−gel method for a new energy conversion device referred to as single-component solid oxide fuel cell (SC-SOFC). The XRD patterns reveal a fluorite cubic structure for all La 2-x Nd x Ce 2 O 7-δ samples. The SEM analysis revealed that La 2-x Nd x Ce 2 O 7-δ (x = 0.5, 1, 1.5) materials exhibit fine agglomeration of irregular grains and nonhomogeneous flakes for the La 2-x Nd x Ce 2 O 7 (x = 0 and 2) samples. Furthermore, FTIR results indicate the presence of nitrates in the composites. In Raman spectra, the F 2g mode is associated with the space group (Fm3m), which confirms the fluorite structure. Further, Raman spectroscopy shows the shifting of peaks to higher frequencies for La 2-x Nd x Ce 2 O 7-δ (x = 0.5, 1, 1.5) samples. The conductivity of La 1.5 Nd 0.5 Ce 2 O 7-δ material shows an exceptional result, with a total conductivity of 0.10 S cm −1 at 600 °C. The Nyquist plot of sample La 1.5 Nd 0.5 Ce 2 O 7-δ shows a reduction of ohmic resistance (R o ) with increasing temperature, confirming the stability for all prepared materials. The La 1.5 Nd 0.5 Ce 2 O 7-δ composite shows a maximum power density of ∼639 mW cm −2 at 600 °C. Therefore, the composite La 2-x Nd x Ce 2 O 7-δ with Ni 0.8 Co 0.15 Al 0.05 LiO 2 as a semionic conductor has good potential as a single-component energy conversion device.