The high operating temperatures and slow kinetics limit the application of MgH_(2)-based hydrogen storage materials.Here,a composite of Ni_(3)ZnC_(0.7)/carbon nanotubes loaded onto a melamine sponge-derived carbon(MS)...The high operating temperatures and slow kinetics limit the application of MgH_(2)-based hydrogen storage materials.Here,a composite of Ni_(3)ZnC_(0.7)/carbon nanotubes loaded onto a melamine sponge-derived carbon(MS)skeleton is prepared and loaded onto MgH_(2).During dehydrogenation,Ni_(3)ZnC_(0.7)reacts with MgH_(2)and in situ changes to Mg_(2)Ni/Zn.The transformation of Mg_(2)Ni/Mg_(2)NiH_(4) serves as a“hydrogen pump”,providing diffusion channels for hydrogen atoms and molecules to promote the de-/hydrogenation processes.Moreover,Zn/MgZn_(2) provides the catalytic sites for the transformation of Mg/MgH_(2).The length of the Mg-H bond is elongated from 1.72 to 1.995Å,and the dissociation energy barrier of MgH_(2)is reduced from 1.55 to 0.49 eV.As a result,MgH_(2)with 2.5 wt%MS@Ni_(3)ZnC_(0.7)can absorb 5.18 wt%H_(2)at 423 K within 200 s,and its initial dehydrogenation temperature is reduced to 585 K.After 20 cycles,the dehydrogenation capacity retention is determined to be 94.6%.This work demonstrates an efficient non-stoichiometric metal carbide catalyst for MgH_(2).展开更多
This study focused on meeting the stringent stability requirements of tubular segmented-in-series solid oxide fuel cells(SOFCs) in reducing and oxidizing atmospheres.To address this challenge,a bi-layer perovskite cer...This study focused on meeting the stringent stability requirements of tubular segmented-in-series solid oxide fuel cells(SOFCs) in reducing and oxidizing atmospheres.To address this challenge,a bi-layer perovskite ceramic interconnect was designed by controlling the oxygen partial pressure,because of the strong correlation between the conductivity of strontium-doped lanthanum titanate(LST) and the oxygen partial pressure.The LST powder was prepared using solid-phase and sol-gel methods,and their influence on particle size and sintering behavior was compared.LST/lanthanum strontium manganite(LSM) bi-layer ceramic interconnects with varying thicknesses were fabricated through screen printing and co-sintering.The results demonstrate favorable interfacial bonding and excellent chemical compatibility between the ceramic layers.The conductivity of the bi-layer interconnect exhibits a temperature-dependent behavior,peaking at 550℃.Simulation calculations and research findings validate that the co nductivity of the bi-layer interconnect is determined by the thickness of the LSM layer and the oxygen partial pressure at the interconnect interface.Optimal conductivity is achieved with a bilayer interconnect consisting of approximately 15 μm of LST and 4 μm of LSM.This can be attributed to the efficient regulation of oxygen partial pressure at the interface,effectively mitigating LSM decomposition caused by low oxygen partial pressure and the subsequent reduction in conductivity.These results provide valuable fundamental data and methodology for the development of high-performance interconnects for tubular segmented-in-series SOFCs.展开更多
This study addresses the challenge of high sintering temperatures in proton-conducting fuel cells(PCFCs)with BaCeO_(3)-doped electrolytes.We demonstrate that 1 mol%copper(Cu)doping at the B-site of BaCe_(0.7)Zr_(0.1)(...This study addresses the challenge of high sintering temperatures in proton-conducting fuel cells(PCFCs)with BaCeO_(3)-doped electrolytes.We demonstrate that 1 mol%copper(Cu)doping at the B-site of BaCe_(0.7)Zr_(0.1)(Dy_(0.1)|Yb_(0.1))_(0.2)O_(3-δ)(BCZDYb)improves sintering behavior,enabling densification at1400℃.However,Cu doping disrupts stoichiometry,creating barium vacancies and reducing protonaccepting cations,affecting overall conductivity.This mechanism is confirmed through density functional theory(DFT)calculations and various experimental techniques,including crystal structure analysis using X-ray diffraction(XRD)and morphology and elemental analysis via field emission scanning electron microscopy(FESEM)and energy-dispersive X-ray spectroscopy(EDS).Electrochemical measurements are performed using the electrochemical impedance spectroscopy(EIS).The ionic conductivity of1 mol%Cu-doped BCZDYb(BCZDYb-1)is 1.49×10^(-2)S cm^(-1)at 650℃,which is~3.58 times higher than that of BCZDYb sintered at 1200℃.The BCZDYb-1 exhibits~16 times higher grain boundary conductivity when sintered at 1400℃,compared to undoped BCZDYb.The single cell employing BCZDYb-1 as the electrolyte achieved a power density of~606 mW cm^(-2)at 550℃.These results indicate that a controlled amount of Cu doping can enhance densification while maintaining high ionic co nductivity,making it suitable for practical applications in PCFCs operating at lower temperatures.展开更多
基金supported by the National Natural Science Foundation of China(No.52101274)the Natural Science Foundation of Shandong Province(Nos.ZR2020QE011 and ZR2022ME089)+2 种基金Youth Top Talent Foundation of Yantai University(No.2219008)Graduate Innovation Foundation of Yantai University(No.GIFYTU2240)College Student Innovation and Entrepreneurship Training Program Project(No.202311066088).
文摘The high operating temperatures and slow kinetics limit the application of MgH_(2)-based hydrogen storage materials.Here,a composite of Ni_(3)ZnC_(0.7)/carbon nanotubes loaded onto a melamine sponge-derived carbon(MS)skeleton is prepared and loaded onto MgH_(2).During dehydrogenation,Ni_(3)ZnC_(0.7)reacts with MgH_(2)and in situ changes to Mg_(2)Ni/Zn.The transformation of Mg_(2)Ni/Mg_(2)NiH_(4) serves as a“hydrogen pump”,providing diffusion channels for hydrogen atoms and molecules to promote the de-/hydrogenation processes.Moreover,Zn/MgZn_(2) provides the catalytic sites for the transformation of Mg/MgH_(2).The length of the Mg-H bond is elongated from 1.72 to 1.995Å,and the dissociation energy barrier of MgH_(2)is reduced from 1.55 to 0.49 eV.As a result,MgH_(2)with 2.5 wt%MS@Ni_(3)ZnC_(0.7)can absorb 5.18 wt%H_(2)at 423 K within 200 s,and its initial dehydrogenation temperature is reduced to 585 K.After 20 cycles,the dehydrogenation capacity retention is determined to be 94.6%.This work demonstrates an efficient non-stoichiometric metal carbide catalyst for MgH_(2).
基金Project supported by the National Key Research and Development Program of China (2021YFB4001400)。
文摘This study focused on meeting the stringent stability requirements of tubular segmented-in-series solid oxide fuel cells(SOFCs) in reducing and oxidizing atmospheres.To address this challenge,a bi-layer perovskite ceramic interconnect was designed by controlling the oxygen partial pressure,because of the strong correlation between the conductivity of strontium-doped lanthanum titanate(LST) and the oxygen partial pressure.The LST powder was prepared using solid-phase and sol-gel methods,and their influence on particle size and sintering behavior was compared.LST/lanthanum strontium manganite(LSM) bi-layer ceramic interconnects with varying thicknesses were fabricated through screen printing and co-sintering.The results demonstrate favorable interfacial bonding and excellent chemical compatibility between the ceramic layers.The conductivity of the bi-layer interconnect exhibits a temperature-dependent behavior,peaking at 550℃.Simulation calculations and research findings validate that the co nductivity of the bi-layer interconnect is determined by the thickness of the LSM layer and the oxygen partial pressure at the interconnect interface.Optimal conductivity is achieved with a bilayer interconnect consisting of approximately 15 μm of LST and 4 μm of LSM.This can be attributed to the efficient regulation of oxygen partial pressure at the interface,effectively mitigating LSM decomposition caused by low oxygen partial pressure and the subsequent reduction in conductivity.These results provide valuable fundamental data and methodology for the development of high-performance interconnects for tubular segmented-in-series SOFCs.
基金supported by the National Key Research and Development Program of China(2021YFB4001400)the Cooperation Project of Shan-dong Energy Group Co.,Ltd.(20200871)supported by 111 Project 2.0(BP0618008).
文摘This study addresses the challenge of high sintering temperatures in proton-conducting fuel cells(PCFCs)with BaCeO_(3)-doped electrolytes.We demonstrate that 1 mol%copper(Cu)doping at the B-site of BaCe_(0.7)Zr_(0.1)(Dy_(0.1)|Yb_(0.1))_(0.2)O_(3-δ)(BCZDYb)improves sintering behavior,enabling densification at1400℃.However,Cu doping disrupts stoichiometry,creating barium vacancies and reducing protonaccepting cations,affecting overall conductivity.This mechanism is confirmed through density functional theory(DFT)calculations and various experimental techniques,including crystal structure analysis using X-ray diffraction(XRD)and morphology and elemental analysis via field emission scanning electron microscopy(FESEM)and energy-dispersive X-ray spectroscopy(EDS).Electrochemical measurements are performed using the electrochemical impedance spectroscopy(EIS).The ionic conductivity of1 mol%Cu-doped BCZDYb(BCZDYb-1)is 1.49×10^(-2)S cm^(-1)at 650℃,which is~3.58 times higher than that of BCZDYb sintered at 1200℃.The BCZDYb-1 exhibits~16 times higher grain boundary conductivity when sintered at 1400℃,compared to undoped BCZDYb.The single cell employing BCZDYb-1 as the electrolyte achieved a power density of~606 mW cm^(-2)at 550℃.These results indicate that a controlled amount of Cu doping can enhance densification while maintaining high ionic co nductivity,making it suitable for practical applications in PCFCs operating at lower temperatures.
