The slow oxygen reaction kinetics of air electrodes impair the performance of reversible protonic ceramic electrochemical cells(R-PCECs);hence,it is imperative to design novel air electrodes featuring excellent cataly...The slow oxygen reaction kinetics of air electrodes impair the performance of reversible protonic ceramic electrochemical cells(R-PCECs);hence,it is imperative to design novel air electrodes featuring excellent catalytic activity and endurance.Here,we report an Rb-doped double perovskite PrBa_(0.8)Ca_(0.1)Rb_(0.1)Co_(2)O_(5+δ)(denoted as PBCR_(0.1)C)as an air electrode for R-PCECs,displaying a low polarization resistance of 0.044Ωcm^(2) at 700℃ and excellent stability during exposure to humid air(3 vol%H_(2)O).The high performance is attributed to the high electrical conductivity,high concentration of oxygen vacancies,and fast surface exchange,as verified by the analyses of X-ray photoelectron spectroscopy,thermogravimetric testing,and conductivity tests.The R-PCECs with the PBCR_(0.1)C air electrode demonstrate an encouraging performance at 700℃:a peak power density of 2.32 W cm^(-2) in a fuel cell(FC)mode and an electrolysis current density of-3.55 A cm^(-2) at 1.3 V in an electrolysis(EL)mode.At 30 vol%steam concentration,a Faraday efficiency of 87.80%and a corresponding H_(2) production rate of 3.05 mL min^(-1) cm^(-2) at a current density of-0.5 A cm^(-2) at 650℃.Additionally,the durability of the cell in the FC mode(120 h),EL mode(120 h),and cycling FC/EL mode(100 h)at 650℃ suggests the great potential of PBCR_(0.1)C as the highly reactive and robust air electrodes of R-PCECs.展开更多
文摘The slow oxygen reaction kinetics of air electrodes impair the performance of reversible protonic ceramic electrochemical cells(R-PCECs);hence,it is imperative to design novel air electrodes featuring excellent catalytic activity and endurance.Here,we report an Rb-doped double perovskite PrBa_(0.8)Ca_(0.1)Rb_(0.1)Co_(2)O_(5+δ)(denoted as PBCR_(0.1)C)as an air electrode for R-PCECs,displaying a low polarization resistance of 0.044Ωcm^(2) at 700℃ and excellent stability during exposure to humid air(3 vol%H_(2)O).The high performance is attributed to the high electrical conductivity,high concentration of oxygen vacancies,and fast surface exchange,as verified by the analyses of X-ray photoelectron spectroscopy,thermogravimetric testing,and conductivity tests.The R-PCECs with the PBCR_(0.1)C air electrode demonstrate an encouraging performance at 700℃:a peak power density of 2.32 W cm^(-2) in a fuel cell(FC)mode and an electrolysis current density of-3.55 A cm^(-2) at 1.3 V in an electrolysis(EL)mode.At 30 vol%steam concentration,a Faraday efficiency of 87.80%and a corresponding H_(2) production rate of 3.05 mL min^(-1) cm^(-2) at a current density of-0.5 A cm^(-2) at 650℃.Additionally,the durability of the cell in the FC mode(120 h),EL mode(120 h),and cycling FC/EL mode(100 h)at 650℃ suggests the great potential of PBCR_(0.1)C as the highly reactive and robust air electrodes of R-PCECs.
