Doped CeO₂–LaFeO₃ Composite Oxide as an Active Anode for Direct Hydrocarbon-Type Solid Oxide Fuel Cells

Direct utilization of hydrocarbon and other renewable fuels is one of the most important issues concerning solid oxide fuel cells (SOFCs). Mixed ionic and electronic conductors (MIECs) have been explored as anode materials for direct hydrocarbon-type SOFCs. However, electrical conductivity of the most often reported MIEC oxide electrodes is still not satisfactory. As a result, mixed-conducting oxides with high electrical conductivity and catalytic activity are attracting considerable interest as an alternative anode material for noncoke depositing anodes. In this study, we examine the oxide composite Ce(Mn,Fe)O2–La(Sr)Fe(Mn)O3 for use as an oxide anode in direct hydrocarbon-type SOFCs. High performance was demonstrated for this composite oxide anode in direct hydrocarbon-type SOFCs, showing high maximum power density of approximately 1 W cm–2 at 1073 K when propane and butane were used as fuel. The high power density of the cell results from the high electrical conductivity of the composite oxide in hydrocarbon and the high surface activity in relation to direct hydrocarbon oxidation

Highly Durable Platinum Catalysts on Nano-SiC Supports with an Epitaxial Graphene Nanosheet Layer Grown from Coffee Grounds for Proton Exchange Membrane Fuel Cells

Robust ceramic supports have attracted significant attention as alternatives to carbon supports for proton exchange membrane fuel cells (PEMFCs). However, they suffer from lower electrocatalytic activities than carbon-based supports because of their electrical conductivity. Here, SiC nanopowders were modified with epitaxial graphene and evaluated as the support for Pt in PEMFCs. Coffee grounds are used as a carbon source to not only enhance the electrocatalytic activity of the graphene-modified SiC supports but also demonstrate the feasibility of exploiting and commercializing this widely available waste product. The Pt-decorated ceramic supports deliver the enhanced durability and performance under the accelerated electro′chemical conditions

Enhancing Bifunctional Catalytic Activity via a Nanostructured La(Sr)Fe(Co)O_3−δ@Pd Matrix as an Efficient Electrocatalyst for Li–O₂ Batteries

One of the important challenges with a bifunctional electrocatalyst is reducing the large overpotential involved in the slow kinetics of the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) at the air electrode in a metal–air redox battery. Here, we present a nanostructured LSCF@Pd matrix of nanostructured LSCF (Nano-LSCF) with palladium to enhance the bifunctional catalytic activity in Li–O2 battery applications. Pd nanoparticles can be perfectly supported on the surface of the Nano-LSCF, and the ORR catalytic activity was properly improved. When Nano-LSCF@Pd was applied to a cathode catalyst in Li–O2 batteries, the first discharge ability (16912 mA h g–1) was higher than that of Nano-LSCF (6707 mA h g–1) and the cycling property improved. These results demonstrate that the Pd-deposited nanostructured perovskite is a capable catalyst to enhance the ORR activity of LSCF as a promising bifunctional electrocatalyst

High-Performance Protonic Ceramic Electrochemical Cells

Protonic ceramic electrochemical cells (PCECs) have attracted considerable attention owing to their ability to reversibly convert chemical fuels into electricity at low temperatures below 600 °C. However, extreme sintering conditions during conventional convection-based heating induce critical problems for PCECs such as nonstoichiometric electrolytes and microstructural coarsening of the electrodes, leading to performance deterioration. Therefore, we fabricated PCECs via a microwave-assisted sintering process (MW-PCEC). Owing to the ultrafast ramping rate (∼50 °C/min) with bipolar rotation and the resistive heating nature of microwave-assisted sintering, undesirable cation diffusion and grain growth were effectively suppressed, thus producing PCECs with stoichiometric electrolytes and nanostructured fuel electrodes. The MW-PCEC achieved electrochemical performance in both in fuel cell (0.85 W cm–2) and in electrolysis cell (1.88 A cm–2) modes at 600 °C (70% and 254% higher than the conventionally sintered PCEC, respectively) demonstrating the effectiveness of using an ultrafast sintering technique to fabricate high-performance PCECs