Sn-doped cobalt containing perovskite as the air electrode for highly active and durable reversible protonic ceramic electrochemical cells

One potential solution to the problems of energy storage and conversion is the use of reversible protonic ceramic electrochemical cells(R-PCEC),which are based on the solid oxide fuel cell(SOFC)technology and offer a flexible route to the generation of renewable fuels.However,the R-PCEC development faces a range of significant challenges,including slow oxygen reaction kinetics,inadequate durability,and poor round-trip efficiency resulting from the inadequacy of an air electrode.To address these issues,we report novel B-sites doped Pr_(0.5)Ba_(0.5)Co_(0.7)Fe_(0.3)O_(3−δ)(PBCF)with varying amounts of Sn as the air electrode for R-PCEC to further enhance electrochemical performance at lower temperatures.At 600℃,R-PCEC with an air electrode consisting of Pr_(0.5)Ba_(0.5)Co_(0.7)Fe_(0.25)Sn_(0.05)O_(3+δ)has achieved peak power density of 1.12 W∙cm^(−2) in the fuel cell mode and current density of 1.79 A∙cm^(−2) in the electrolysis mode at a voltage of 1.3 V.Moreover,R-PCECs have shown good stability in the electrolysis mode of 100 h.This study presents a practical method for developing durable high-performance air electrodes for R-PCECs.

A comprehensive review of recent progresses in cathode materials for Proton-conducting SOFCs

Solid oxide fuel cells(SOFCs)are widely recognized as efficient energy sources that have the potential to shape the future of energy development.Among various types of SOFCs,the low-temperature operation of protonconducting SOFCs(H–SOFCs)offers distinct advantages for wide commercialization compared to oxygen-ion conducting SOFCs(O–SOFCs).However,the commercialization of H–SOFCs is hindered by several challenges,including slow oxygen reduction kinetics and long-term instability of cathode materials.The electrochemical performance of the cathode system in H–SOFCs is limited by the poor proton conductivity of the cathode material and the scarcity of surface reaction sites.Additionally,the presence of undesirable phases induced by elements such as Cr and CO_(2)adversely affects the chemical stability and catalytic activity of the cathode.Thermal stress arising from the mismatch in coefficient of thermal expansion between the cathode and electrolyte further adds to the challenges.Therefore,this comprehensive review presents underlying mechanisms and potential solutions to overcome the challenges in H–SOFCs,leading to higher efficiency and wider commercialization of H–SOFCs.