Development of the combinatorial high-throughput system to investigate highly potential electrocatalysts in fuel cells and Li-air batteries

Abstract

The search of alternatives to Pt-based catalysts for oxygen reduction reactions (ORRs) in both polymer electrolyte membrane fuel cells (PEMFCs) and Lithium-air batteries (Li-air) were conducted through the combinatorial high-throughput method and the selected non-Pt catalysts were synthesized and characterized. Transition metal-based materials are one of the most widely used heterogeneous catalysts in these systems because of their high activity in many important reactions. However, as the non-Pt based catalysts face issues of lower activity and stability compared to the Pt-based catalysts, various attempts in combination between these non-Pt elements have been studied to overcome issues regarding the commercialization of these devices. Synthesis of the optimized catalysts is however still challenging due to the boundless variations of possible combinations and compositions among the chemical elements. To remedy this issue, the combinatorial high-throughput technology, especially the combinatorial half-cell test and the optical screening, has been developed for efficient and simultaneous assessment of diverse catalyst libraries. Combinatorial optical screening of aprotic electrocatalysts has yet not been achieved primarily due to $H^+$ -associated mechanisms of fluorophore modulation. We have overcome this problem by using fluorophore metal-organic complexes.