Factors Constituting Proton Trapping in BaCeO3 and BaZrO3 Perovskite Proton Conductors in Fuel Cell Technology: A Review

Urbanization with increasing demand for energy at a rapid pace has prompted researchers to explore effective and efficient energy storage technology. Fuel cells, being well-known among other existing devices, are categorized based on the nature of the electrolyte employed. In several areas, proton conduction solid oxide fuel cells have surpassed conventional solid oxide fuel cells. Nonetheless, there still prevail drawbacks accompanied with the proton-conducting electrolyte materials. However, the disadvantages associated with proton-conducting electrolytic materials persists. Besides chemical stability, one of the significant concerns is the fluctuation in proton conductivity among acceptor-doped compositions. Recent introspection interprets the proton trapping effect in the vicinity of the substituent attenuating proton mobility, the fundamentals of which point toward a proton-dopant complex interaction and altering basicity of the dopant neighboring oxygen atoms, escalating the activation energy. This implies a pronounced affinity of proton-trapped sites in the close coordination of the acceptor dopant while implying trap-free sites elsewhere. In the following review article, we direct our attention to the assimilation of factors responsible for the genesis of proton trapping sites with an additional motive to explore the optimal composition while achieving maximum productivity.