Realizing Simultaneous Detrimental Reactions Suppression and Multiple Benefits Generation from Nickel Doping toward Improved Protonic Ceramic Fuel Cell Performance

Anode-supported protonic ceramic fuel cells (PCFCs) are highly promising and efficient energy conversion systems. However, several challenges need to be overcome before these systems are used more widely, including the poor sintering of recently developed proton-conducting oxides and the decreased proton conductivity due to detrimental reactions between the nickel from anode and the electrolyte occurring during high-temperature co-sintering. Herein, a Ni doping strategy to increase the electrolyte sintering, suppress the detrimental phase reactions, and generate stable Ni nanoparticles for enhanced performance is proposed. A nickel-doped perovskite oxide is developed with the nominal composition of Ba(Zr_0.1Ce_0.7Y_0.1Yb_0.1)_0.95Ni_0.05O_3−δ. Acting as a sintering aid, such a small amount of nickel effectively improves the sintering of the electrolyte. Concomitantly, reactions between nickel and the Ni-doped ceramic phase are suppressed, turning detrimental phase reactions into benefits. The nickel doping further promotes the formation of Ni nanoparticles, which enhance the electrocatalytic activity of the anode toward the hydrogen oxidation reaction and improve the charge transfer across the anode–electrolyte interface. As a result, highly efficient PCFCs are developed. The innovative anode developed in this work also shows favorable activity toward ammonia decomposition, making it highly promising for use in direct ammonia fuel cells.