Solid Oxide Cell Electrode Material for On-demand Production of Hydrogen and Electricity

Abstract

Reversible solid oxide cells (RSOCs) can revolutionize energy production, enabling on-demand hydrogen and electricity production and addressing the intermittent supply of renewable energy. However, their commercialization has been hindered by the lack of materials that can efficiently function as both a solid oxide electrolytic cell and a solid oxide fuel cell electrode. This research aims to address this challenge by developing a novel perovskite material that can meet the multiple electrochemical requirements of RSOCs, potentially accelerating the commercialization of this promising technology. Developing materials that are capable of enhancing the exsolution process offers some possibilities for solving this problem. Exsolution entails the segregation of metallic cations to form highly active and anchored nanoparticles on the surface of a perovskite lattice – enhancing catalytic and electrochemical stability in the material. Forming such nanoparticles within the bulk of the perovskite lattice (bulk exsolution) has recently improved ionic conductivity. This research there sought to develop a novel perovskite material that is capable of surface and bulk exsolution processes to fulfil the stability and electrochemical requirements of RSOCs. Five potential precursor materials were studied to ascertain their suitability and develop a synthesis route for the novel perovskite material. The study involved detailed characterisation of the potential precursor materials via thermogravimetry analysis (TGA), scanning electron microscopy (SEM), and X-ray diffraction (XRD) analysis. The TGA results revealed Fe2O3, NiO, SrO and CaO as the decomposition products of the respective precursor materials, which are useful oxides desired in the novel perovskite. Only TiO2¬ is stable within the other precursors' decomposition temperature range (50 – 900 oC). The TGA result, therefore, predicted that the chemical reaction to form the desired perovskite will likely be in the temperature range of 600 – 1000 oC. Hence, a modified solid-state synthesis method was adopted for the novel perovskite synthesis. In the two different compositions of the perovskite samples, it has been observed that homogeneous mixing of the precursors before their calcination encouraged homogeneous dispersion of species in the samples.