Development of Efficient Triple-conducting Electrode for Protonic Ceramic Electrolysis/Fuel Cells
Dr. Nikhil Kumar
CSIR-National Metallurgical Laboratory (NML)
Scientist
Energy generation and its environmental effects, the invention of clean and renewable electrochemical energy generation, conversion and storage have paramount importance and have attracted a large amount of research. Protonic ceramic cells (PCCs) including electrolysis/fuel cells (PCECs/PCFCs) have intermediate-temperature (400–600°C) applications for reversible conversion between chemical and electrical energy with high efficiency and zero emissions. The PCC technology has been driving a fast-increasing research direction in recent years, considered as a potential alternative to traditional combustion-based engines, power plants, and batteries, which consists of high cost, requires more capital and infrastructure investment, and releases a significant amount of carbon dioxide (CO2) annually. Although, the direct photocatalytic or electrocatalytic conversion H2, as an energy carrier into H2O is a sustainable process, the conversion efficiency and the production rate remain low. Hence, the design and development of rational catalyst with efficient electrocatalysis become primary necessity and central element to improve the efficiency and future capability of this cell technology. Ruddlesden-Popper phase layered perovskites oxides with high specific catalytic activity, different physical, chemical, optical and electronic such as ionic and conduction properties, wide elemental tolerance with excellent durability favoured them as emerging oxygen evolution/ reduction reaction (OER/ORR) catalyst have already been reported. A simple sol-gel method has applied for the synthesis of perovskite oxide (Ni, Co, Fe, Mn) based electrodes and electrolytes. Characterizations involve PXRD for phase purity, FESEM to know the particle size, AFM for surface roughness, EDAX for elemental analysis, XPS to get the idea of oxidation states and orbital contribution of each metal ions. H2 electrode-supported cells (Ni or V) fabricated by electrolyte through sputtering or spin coated process followed by post annealing in inert gas atmosphere and sintering. A dense film/layer of electrolyte (1-2 nm) deposits on metal-based electrode. The composite material for cathode is prepared by mixing OER/ORR catalyst and electrolyte or ORR catalyst and porous inert ceramics for hydrothermal stability and printed over electrolyte layer using screen printing (3 nm) of OER/ORR catalyst based composite. The prepared cell is sinter again at high temperature to provide the stability as well as good contact between electrode–electrolyte bilayer.