Homogeneous co-precipitation and hydrothermal treatment were used to prepare nano- and highly dispersed Ni O/YSZ(yttria-stabilized zirconia) composite powders. Composite powders of size less than 100 nm were successfu...Homogeneous co-precipitation and hydrothermal treatment were used to prepare nano- and highly dispersed Ni O/YSZ(yttria-stabilized zirconia) composite powders. Composite powders of size less than 100 nm were successfully prepared. This process did not require separate sintering of the YSZ and Ni O to be used as the raw materials for solid oxide fuel cells. The performance of a cell fabricated using the new powders(max.power density ~0.87 W/cm^2) was higher than that of a cell fabricated using conventional powders(max. power density ~0.73 W/cm^2). Co-precipitation and hydrothermal treatment proved to be very effective processes for reducing cell production costs as well as improving cell performance.展开更多
Performance degradation shortens the life of solid oxide fuel cells in practical applications.Revealing the degradation mechanism is crucial for the continuous improvement of cell durability.In this work,the effects o...Performance degradation shortens the life of solid oxide fuel cells in practical applications.Revealing the degradation mechanism is crucial for the continuous improvement of cell durability.In this work,the effects of cell operating conditions on the terminal voltage and anode microstructure of a Ni-yttria-stabilized zirconia anode-supported single cell were investigated.The microstructure of the anode active area near the electrolyte was characterized by laser optical microscopy and focused ion beam-scanning electron microscopy.Ni depletion at the anode/electrolyte interface region was observed after 100 h discharge tests.In addition,the long-term stability of the single cell was evaluated at 700℃for 3000 h.After an initial decline,the anode-supported single cell exhibits good durability with a voltage decay rate of 0.72%/kh and an electrode polarization resistance decay rate of 0.17%/kh.The main performance loss of the cell originates from the initial degradation.展开更多
NiO/SDC composites and Ni/SDC cermets for solid oxide fuel cell （SOFC） anode applications were prepared from nickel oxide （NiO） and samada doped ceria （SDC） powders by the powder metallurgy process. The physical...NiO/SDC composites and Ni/SDC cermets for solid oxide fuel cell （SOFC） anode applications were prepared from nickel oxide （NiO） and samada doped ceria （SDC） powders by the powder metallurgy process. The physical and mechanical properties, as well as the microstructure of the NiO/SDC composites and the Ni/SDC cermets were investigated. It is shown that the sintedng temperature of the NiO/SDC composites and NiO content plays an important role in determining the microstructure and properties of the NiO/SDC composites, which, in turn, influences the microstructure, electrical conductivity, and mechanical properties of the Ni/SDC cermets. The present study demonstrated that composition and tprocess parameters must be appropriately selected to optimize the microstructure and the properties of NiO/SDC materials for solid oxide fuel cell applications.展开更多
Ni-based anodes of SOFCs are susceptible to coking, which greatly limits practical application of direct methane-based fuels. An indirect internal reformer is an effective way to convert methane-based fuels into synga...Ni-based anodes of SOFCs are susceptible to coking, which greatly limits practical application of direct methane-based fuels. An indirect internal reformer is an effective way to convert methane-based fuels into syngas before they reach anode. In this work, catalytic activity of a redox-stable perovskite La0.7Sr0.3Cr0.8Fe0.2O3-δ(LSCrFO) for methane conversion was evaluated. The catalyst was fabricated as an anodic protective layer to improve coking resistance of a Ni cermet anode. Using wet CH4 as a fuel, the LSCrFO-modified cell showed excellent power output and good coking resistance with peak power density of 1.59 W cm-2 at 800℃. The cell demonstrated good durability lasting for at least 100 h. While the bare cell without the protective layer showed poor durability with the cell voltage fast dropped from 0.75 V to 0.4 V within 30 min. Under wet coal bed methane (CBM) operation, obvious performance degradation within 35 h (1.7 mV h^-1) was observed due to the influence of heavy carbon compounds in CBM. The pre-and post-mortem microstructures and carbon analysis of the anode surface and catalyst surface were further conducted.展开更多
The effect of temperature on the characteristics of gallium nitride (GaN) Schottky barrier diodes (SBDs) with TiN and Ni anodes is evaluated. With increasing the temperature from 25 to 175℃, reduction of the turn-on ...The effect of temperature on the characteristics of gallium nitride (GaN) Schottky barrier diodes (SBDs) with TiN and Ni anodes is evaluated. With increasing the temperature from 25 to 175℃, reduction of the turn-on voltage and increase of the leakage current are observed for both GaN SBDs with TiN and Ni anodes. The performance after thermal treatment shows much better stability for SBDs with Ti N anode, while those with Ni anode change due to more interface states. It is found that the leakage currents of the GaN SBDs with TiN anode are in accord with the thermionic emission model whereas those of the GaN SBDs with Ni anode are much higher than the model. The Silvaco TCAD simulation results show that phonon-assisted tunneling caused by interface states may lead to the instability of electrical properties after thermal treatment, which dominates the leakage currents for GaN SBDs with Ni anode. Compared with GaN SBDs with Ni anode, GaN SBDs with TiN anode are beneficial to the application in microwave power rectification fields due to lower turn-on voltage and better thermal stability.展开更多
Lithium metal,as the most ideal anode material for high energy density batteries,has been researched for several decades.However,the dendrite formation and large volume change during repetitive lithium plating/strippi...Lithium metal,as the most ideal anode material for high energy density batteries,has been researched for several decades.However,the dendrite formation and large volume change during repetitive lithium plating/stripping lead to a serious safety issue and impede the practical application of lithium metal anode.Herein,a nanoporous Ni foam current collector with high surface area and surface flaws is constructed via a facile oxidation-reduction method.The inherent macropore structure of Ni foam can partly accommodate the volume variation during Li plating/stripping.The well-distributed nanopores on the skeleton of Ni foam can effectively reduce the local current density,regulate the uniform lithium nucleation and deposition with homogenous distribution of Li^(+) flux.Moreover,the surface flaws induce the formation of ring Li structures at initial nucleation/deposition processes and concave Li metal spontaneously formed based on the ring Li structures during cycling,which can direct the even Li plating/stripping.Therefore,highly stable Coulombic efficiency is achieved at 1 mA cm^(-2) for 200 cycles.The symmetrical cell,based on the nanoporous Ni foam current collector,presents long lifespans of 1200 and 700 h respectively at different current densities of 0.5 and 1 mA cm^(-2) without short circuit.In addition,the LiFePO4 full cell,with the Li metal anode based on the nanoporous Ni foam current collector,shows excellent cycling performance at 1 C for 300 cycles and rate performance.展开更多
Building three-dimensional(3D) current collectors is a promising strategy to surmount the bottlenecks of lithium metal anodes(LMAs), but the regulation methodology of a 3D current collector has seldom been considered ...Building three-dimensional(3D) current collectors is a promising strategy to surmount the bottlenecks of lithium metal anodes(LMAs), but the regulation methodology of a 3D current collector has seldom been considered comprehensively concerning both skeleton architectures and surface coatings. Herein, a robust porous 3D nickel skeleton(NS) with lithiophilic NiN nanocoatings(NiN@NS) is synthesized via an integrative route of powder metallurgy/plasma-enhanced nitridation technics. The facile powder metallurgical method facilitates the adjustment of NS architectures toward sufficient electrolyte adsorption and even current density distribution, while the followed plasma-enhanced chemical vapor deposition(PECVD) method can induce compact NiN nanocoatings on NS, which reduces the Li nucleation overpotential, accelerates the Li-ion transfer, and facilitates a highly reversible oriented texture of Li deposition morphology owing to the dense and homogenous deposition of Li into the pores. The optimized NiN@NS current collector shows a high averaged Coulombic efficiency(CE) of 98.8% over 350cycles, a prolonged lifespan of 1000 h(at 2 mA cm^(-2)) in symmetrical cells, together with the significant performance in full cells. The ingenious methodology reported in this work can also be broadly applicable for the controllable production of other 3D skeletons with nitride nanocoatings for various applications.展开更多
Nickel anode was investigated as a potential anode of aluminium electrowinning for preparation of Al-Ni master alloys. The electrolysis tests were carried out in Na3AlF6-Al2O3 based melts at 940 ℃. The results show t...Nickel anode was investigated as a potential anode of aluminium electrowinning for preparation of Al-Ni master alloys. The electrolysis tests were carried out in Na3AlF6-Al2O3 based melts at 940 ℃. The results show that the cell voltage during electrolysis has only minor instability,and there exists NiO phase in electrolyte after 0.5 h electrolysis. Ni content in Al-Ni master alloys increases with increasing the electrolysis time. Concentration limit of Ni in Al-Ni master alloys can be up to 33.8%(mass fraction). However,substantial corrosion of the Ni-metal substrate is observed,and the oxide scale on the nickel anode after electrolysis is porous and loose that does not prevent corrosion of the substrate.展开更多
基金supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2012R1A1A1013782)a fostering project funded by the Ministry of Education, Science and Technology (MEST)
文摘Homogeneous co-precipitation and hydrothermal treatment were used to prepare nano- and highly dispersed Ni O/YSZ(yttria-stabilized zirconia) composite powders. Composite powders of size less than 100 nm were successfully prepared. This process did not require separate sintering of the YSZ and Ni O to be used as the raw materials for solid oxide fuel cells. The performance of a cell fabricated using the new powders(max.power density ~0.87 W/cm^2) was higher than that of a cell fabricated using conventional powders(max. power density ~0.73 W/cm^2). Co-precipitation and hydrothermal treatment proved to be very effective processes for reducing cell production costs as well as improving cell performance.
基金supported by the National Key R&D Program of China(No.2018YFB1502202)the Fundamental Research Funds for the Central Universities(No.FRF-GF-20-09B).
文摘Performance degradation shortens the life of solid oxide fuel cells in practical applications.Revealing the degradation mechanism is crucial for the continuous improvement of cell durability.In this work,the effects of cell operating conditions on the terminal voltage and anode microstructure of a Ni-yttria-stabilized zirconia anode-supported single cell were investigated.The microstructure of the anode active area near the electrolyte was characterized by laser optical microscopy and focused ion beam-scanning electron microscopy.Ni depletion at the anode/electrolyte interface region was observed after 100 h discharge tests.In addition,the long-term stability of the single cell was evaluated at 700℃for 3000 h.After an initial decline,the anode-supported single cell exhibits good durability with a voltage decay rate of 0.72%/kh and an electrode polarization resistance decay rate of 0.17%/kh.The main performance loss of the cell originates from the initial degradation.
基金This work was financially supported by the National Key Fundamental Research and Development Program of China (No. G2000026409).
文摘NiO/SDC composites and Ni/SDC cermets for solid oxide fuel cell （SOFC） anode applications were prepared from nickel oxide （NiO） and samada doped ceria （SDC） powders by the powder metallurgy process. The physical and mechanical properties, as well as the microstructure of the NiO/SDC composites and the Ni/SDC cermets were investigated. It is shown that the sintedng temperature of the NiO/SDC composites and NiO content plays an important role in determining the microstructure and properties of the NiO/SDC composites, which, in turn, influences the microstructure, electrical conductivity, and mechanical properties of the Ni/SDC cermets. The present study demonstrated that composition and tprocess parameters must be appropriately selected to optimize the microstructure and the properties of NiO/SDC materials for solid oxide fuel cell applications.
基金supported by the Coal Seam Gas Joint Foundation of Shanxi(2015012016)Shanxi Province Science Foundation(2016011025)+2 种基金Shanxi Scholarship Council of China(2016-010)Shanxi “1331 Project” Key Innovative Research Team(“1331KIRT”)the Open Funding from State Key Laboratory of Materialoriented Chemical Engineering(No.KL16-03)
文摘Ni-based anodes of SOFCs are susceptible to coking, which greatly limits practical application of direct methane-based fuels. An indirect internal reformer is an effective way to convert methane-based fuels into syngas before they reach anode. In this work, catalytic activity of a redox-stable perovskite La0.7Sr0.3Cr0.8Fe0.2O3-δ(LSCrFO) for methane conversion was evaluated. The catalyst was fabricated as an anodic protective layer to improve coking resistance of a Ni cermet anode. Using wet CH4 as a fuel, the LSCrFO-modified cell showed excellent power output and good coking resistance with peak power density of 1.59 W cm-2 at 800℃. The cell demonstrated good durability lasting for at least 100 h. While the bare cell without the protective layer showed poor durability with the cell voltage fast dropped from 0.75 V to 0.4 V within 30 min. Under wet coal bed methane (CBM) operation, obvious performance degradation within 35 h (1.7 mV h^-1) was observed due to the influence of heavy carbon compounds in CBM. The pre-and post-mortem microstructures and carbon analysis of the anode surface and catalyst surface were further conducted.
基金Supported by the National Key Research and Development Plan under Grant No 2017YFB0403000the Fundamental Research Funds for the Central Universities under Grant No JB181110
文摘The effect of temperature on the characteristics of gallium nitride (GaN) Schottky barrier diodes (SBDs) with TiN and Ni anodes is evaluated. With increasing the temperature from 25 to 175℃, reduction of the turn-on voltage and increase of the leakage current are observed for both GaN SBDs with TiN and Ni anodes. The performance after thermal treatment shows much better stability for SBDs with Ti N anode, while those with Ni anode change due to more interface states. It is found that the leakage currents of the GaN SBDs with TiN anode are in accord with the thermionic emission model whereas those of the GaN SBDs with Ni anode are much higher than the model. The Silvaco TCAD simulation results show that phonon-assisted tunneling caused by interface states may lead to the instability of electrical properties after thermal treatment, which dominates the leakage currents for GaN SBDs with Ni anode. Compared with GaN SBDs with Ni anode, GaN SBDs with TiN anode are beneficial to the application in microwave power rectification fields due to lower turn-on voltage and better thermal stability.
基金the National Natural Science Foundation of China(No.51761135123)the National Key Research&Development Program(2016YFB0303903,2016YFE0201600)。
文摘Lithium metal,as the most ideal anode material for high energy density batteries,has been researched for several decades.However,the dendrite formation and large volume change during repetitive lithium plating/stripping lead to a serious safety issue and impede the practical application of lithium metal anode.Herein,a nanoporous Ni foam current collector with high surface area and surface flaws is constructed via a facile oxidation-reduction method.The inherent macropore structure of Ni foam can partly accommodate the volume variation during Li plating/stripping.The well-distributed nanopores on the skeleton of Ni foam can effectively reduce the local current density,regulate the uniform lithium nucleation and deposition with homogenous distribution of Li^(+) flux.Moreover,the surface flaws induce the formation of ring Li structures at initial nucleation/deposition processes and concave Li metal spontaneously formed based on the ring Li structures during cycling,which can direct the even Li plating/stripping.Therefore,highly stable Coulombic efficiency is achieved at 1 mA cm^(-2) for 200 cycles.The symmetrical cell,based on the nanoporous Ni foam current collector,presents long lifespans of 1200 and 700 h respectively at different current densities of 0.5 and 1 mA cm^(-2) without short circuit.In addition,the LiFePO4 full cell,with the Li metal anode based on the nanoporous Ni foam current collector,shows excellent cycling performance at 1 C for 300 cycles and rate performance.
基金supported by the National Natural Science Foundation of China(U1904216)。
文摘Building three-dimensional(3D) current collectors is a promising strategy to surmount the bottlenecks of lithium metal anodes(LMAs), but the regulation methodology of a 3D current collector has seldom been considered comprehensively concerning both skeleton architectures and surface coatings. Herein, a robust porous 3D nickel skeleton(NS) with lithiophilic NiN nanocoatings(NiN@NS) is synthesized via an integrative route of powder metallurgy/plasma-enhanced nitridation technics. The facile powder metallurgical method facilitates the adjustment of NS architectures toward sufficient electrolyte adsorption and even current density distribution, while the followed plasma-enhanced chemical vapor deposition(PECVD) method can induce compact NiN nanocoatings on NS, which reduces the Li nucleation overpotential, accelerates the Li-ion transfer, and facilitates a highly reversible oriented texture of Li deposition morphology owing to the dense and homogenous deposition of Li into the pores. The optimized NiN@NS current collector shows a high averaged Coulombic efficiency(CE) of 98.8% over 350cycles, a prolonged lifespan of 1000 h(at 2 mA cm^(-2)) in symmetrical cells, together with the significant performance in full cells. The ingenious methodology reported in this work can also be broadly applicable for the controllable production of other 3D skeletons with nitride nanocoatings for various applications.
基金Projects (50334030 50304005) supported by the National Natural Science Foundation of ChinaProject (20041010) supported by Ph.D Fund of Liaoning Province, China
文摘Nickel anode was investigated as a potential anode of aluminium electrowinning for preparation of Al-Ni master alloys. The electrolysis tests were carried out in Na3AlF6-Al2O3 based melts at 940 ℃. The results show that the cell voltage during electrolysis has only minor instability,and there exists NiO phase in electrolyte after 0.5 h electrolysis. Ni content in Al-Ni master alloys increases with increasing the electrolysis time. Concentration limit of Ni in Al-Ni master alloys can be up to 33.8%(mass fraction). However,substantial corrosion of the Ni-metal substrate is observed,and the oxide scale on the nickel anode after electrolysis is porous and loose that does not prevent corrosion of the substrate.
