Operando dynamic self-assembly of bifunctional electrocatalysts for high-performance symmetric molten carbonate cells

Abstract

Molten carbonate cells (MCCs) present a promising pathway for simultaneous power generation, fuel production, and CO2 utilization; however, several challenges remain in their practical application, particularly due to sluggish oxygen electrode kinetics. In this study, we introduce a high-performance symmetric MCC featuring a dynamic self-assembly La-electrode fabricated via a straightforward single-element dip-coating process. During the cell start-up process, the phase transition behavior of the La-Ni-O system induces autonomous surface reconstruction into hierarchical nano- to microscale structures that enable powerful dual electrocatalysis: LaNiO3 nano perovskite oxides at the air electrode and exsolved Ni nanoparticles on La2O3 at the fuel electrode. These distinctive architectures offer abundant active sites, accelerate both electrode reaction kinetics, and ensure uniform electrolyte distribution, thereby facilitating highly efficient and stable MCC operation. Consequently, the La-symmetric cell demonstrates an electrolysis voltage of 1.09 V (at −150 mA cm−2, 650 °C) with 90 % efficiency, achieving a 60 % reduction in polarization resistance compared to conventional electrodes, while concurrently simplifying the cell fabrication and assembly processes. Our study provides a framework for next-generation MCCs, emphasizing their significant potential as practical platforms for clean energy conversion.