Novel materials for solid oxide fuel cell technologies: A literature review

Development of lanthanum strontium cobalt ferrite perovskite electrodes of solid oxide fuel cells – A review

Proton-conducting oxides are a class of solid-state ion-conducting ceramic materials that demonstrate significant hydrogen ion (proton) conductivity at intermediate temperatures (e.g., 300–700 °C). They are garnering significant attention due to several unique characteristics that distinguish them from both higher temperature oxygen ion conducting oxides and lower temperature proton-conducting polymers. By enabling proton-mediated electrochemistry under both dry and wet environments at moderate temperatures, protonic ceramics provide unique opportunities to enhance or synergize a diverse range of complementary electrochemical and thermochemical processes. Because of this potential, significant efforts have been devoted to advancing numerous energy-related applications using these materials. This review aims to comprehensively summarize these applications and analyze the most up-to-date and future developments of proton-conducting oxides. We aim to bring together this diverse subject matter by integrating the fundamentals of proton-conducting oxides with application-oriented insights. We begin with a historical roadmap, followed by a basic overview of the materials, theories and fundamentals, and fabrication and processing technologies underlying the field. The central section of our review summarizes major applications and developments of proton-conducting ceramics, ranging from maturing applications approaching commercialization to embryonic technologies just now emerging from the lab. These include protonic ceramic fuel cells, protonic ceramic electrolysis cells, reversible protonic ceramic electrochemical cells, protonic ceramic membrane reactors, and protonic ceramic electrochemical reactors. For each application, we analyze both the prospects and challenges and offer recommendations for future research directions so that tomorrow's researchers can continue to advance the development and commercialization of these fascinating materials.

Proton-conducting oxides for energy conversion and storage

The protonic ceramic electrochemical cell (PCEC) is an emerging and attractive technology that converts energy between power and hydrogen using solid oxide proton conductors at intermediate temperatures. To achieve efficient electrochemical hydrogen and power production with stable operation, highly robust and durable electrodes are urgently desired to facilitate water oxidation and oxygen reduction reactions, which are the critical steps for both electrolysis and fuel cell operation, especially at reduced temperatures. In this study, a triple conducting oxide of PrNi0.5Co0.5O3-δ perovskite is developed as an oxygen electrode, presenting superior electrochemical performance at 400~600 °C. More importantly, the self-sustainable and reversible operation is successfully demonstrated by converting the generated hydrogen in electrolysis mode to electricity without any hydrogen addition. The excellent electrocatalytic activity is attributed to the considerable proton conduction, as confirmed by hydrogen permeation experiment, remarkable hydration behavior and computations.

/pdf/self-sustainable-protonic-ceramic-electrochemical-cells-o158apg8a5.pdf

Self-sustainable protonic ceramic electrochemical cells using a triple conducting electrode for hydrogen and power production.

Energy crisis and environmental problems urgently drive the proposal of new strategies to improve human wellbeing and assist sustainable development. To this end, scientists have explored many metal oxides-based photocatalysts with high stability, low cost, earth abundance, and potentially high catalytic activity relevant for key applications such as H2O splitting, CO2 reduction, N2 fixation, and advanced oxidation of pollutants. In these metal oxides, oxygen vacancies (OVs) are ubiquitous and intrinsic defects with pronounced impacts on the physicochemical properties of the catalysts, which may open new opportunities for obtaining efficient metal oxides. The thorough understanding of the structural and electronic nature of OVs is necessary to determine how they serve as catalytically active sites. In this review, we summarize the origin of OVs, the strategies to introduce OVs, as well as the fundamental structure-activity relationships to relate these crystal defects to catalyst properties including light absorption, charge separation, etc. We emphasize the mechanism of OVs formation and their effects on the intrinsic catalytic characteristics of the metal oxides. We also present some multicomponent catalytic platforms where OVs contribute to catalysis via synergy. Finally, opportunities and challenges on engineering defects in photocatalysts are summarized to highlight the future directions of this research field.

/pdf/oxygen-vacancies-in-metal-oxides-recent-progress-towards-3ugmuehdqb.pdf

Oxygen vacancies in metal oxides: recent progress towards advanced catalyst design

La2 − xPrxNiO4 + δ as suitable cathodes for metal supported SOFCs

https://hal.archives-ouvertes.fr/hal-01360432/document

Clément Nicollet

Papers

La2 − xPrxNiO4 + δ as suitable cathodes for metal supported SOFCs

An innovative efficient oxygen electrode for SOFC: Pr6O11 infiltrated into Gd-doped ceria backbone

Chemical and structural changes in Ln2NiO4+δ (Ln=La, Pr or Nd) lanthanide nickelates as a function of oxygen partial pressure at high temperature

La2NiO4+δ infiltrated into gadolinium doped ceria as novel solid oxide fuel cell cathodes: Electrochemical performance and impedance modelling

Identification and modelling of the oxygen gas diffusion impedance in SOFC porous electrodes: application to Pr2NiO4+δ