Promotion of Reversible Fuel-Power Generation in Protonic Ceramic Electrochemical Cell via Water-Mediated Ex-Solution

It is indicated that water can be an active motif for nanoparticle ex-solution. Yet, only a handful of studies are available, if possible, limited to the elemental composition of Ba(Co,Fe,Zr,Y)O3−δ as a mother oxide. Here we prove the versatility of water-mediated ex-solution by expanding the perovskite palettes. Among these, our selected composition (i.e., Ag ex-solved Ba0.95Ag0.05Co0.8Nb0.1Ta0.1O3-δ, e-BACNT) is demonstrated as an oxygen electrode material for protonic ceramic electrochemical cells, promoting efficient reversible fuel-power generation. Thereby, a peak power density of ∼1.81 W cm–2 and water-splitting current density of ∼2.93 A cm–2 at 1.3 V and 650 °C are achieved within a single cell. Apart from its notable cell performances, this work unveils new opportunities for creating functional metal-oxide heterointerfaces.