High-performance solid oxide fuel cell(SOFC) is in urgent need of high-quality electrolyte powders with high reactivity and chemical uniformity.Here,8 mol% Y_(2)O_(3) doped ZrO_(2)(YSZ) nano-powders were synthesized b...High-performance solid oxide fuel cell(SOFC) is in urgent need of high-quality electrolyte powders with high reactivity and chemical uniformity.Here,8 mol% Y_(2)O_(3) doped ZrO_(2)(YSZ) nano-powders were synthesized by an improved solid-state reaction method at ambient temperature,and were applied to the fabrication of SOFC electrolytes.YSZ nano-powders show average grain sizes of ^(2)0 nm and high dispersibility,which is comparable with or even better than some other chemical methods.Benefitting from their high reactivity,dense YSZ electrolytes(relative density of 97.9%) can be obtained at a relatively low sintering temperature of 1400℃.The optimized electrical conductivity reaches up to a high value of0.034 S/cm at 800 0C in air.The anode supported single cell with the construction of Ni-YSZ/YSZ/Sm_(0.2)Ce_(0.8)O_(2-δ)(SDC)/La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3-δ)(LSCF) exhibits the peak power density of 0.827 W/cm^(2) at800℃ while taking wet H_(2) as fuels and ambient air as oxidants.展开更多
To address the growing demand for radar and infrared stealth materials in complex application scenarios,this study develops an integrated multifunctional composite through a vacuum impregnation process that combines S...To address the growing demand for radar and infrared stealth materials in complex application scenarios,this study develops an integrated multifunctional composite through a vacuum impregnation process that combines SiCN ceramics,porous ceramics,and phase change materials(PCMs).The unmodified SiCN ceramic,as a standalone component,exhibits a minimum reflection loss(RL_(min))of-14.91 dB,demonstrating its intrinsic electromagnetic absorption capability.When integrated into the composite,the porous ceramic matrix optimizes impedance matching,synergistically enhancing the overall microwave absorption performance.The resulting composite achieves RL_(min) of-31.29 dB with an effective absorption bandwidth(EAB)covering 96%of the X-band(8.2-12.4 GHz).Furthermore,the PCM embedded within the pores utilizes its latent heat during phase transition to regulate temperature fluctuations.When subjected to heating at 90℃(exceeding the PCM solid-liquid transition temperature)for 42 min,the composite exhibits a temperature rise of only 16.5℃,maintaining a 36.6℃difference from the external thermal load.This special thermal buffering capability ensures stable thermal insulation and infrared stealth functions while improving the electromagnetic response stability of the material under dynamic thermal conditions.The proposed design strategy offers new insights for advancing multifunctional electromagnetic wave(EMW)absorbing materials with enhanced performance adaptability.展开更多
In this review,we summarize the research activities carried out by our research group at the University of Padova on the additive manufacturing of ceramics from liquid feedstocks.Particularly,we evaluate the use of pr...In this review,we summarize the research activities carried out by our research group at the University of Padova on the additive manufacturing of ceramics from liquid feedstocks.Particularly,we evaluate the use of preceramic polymers,geopolymers,and sol-gel solutions.We mainly focus on processing with liquid feedstocks because they have some advantages with respect to slurry-based feedstocks in which powders are present.Particularly,lower viscosity,enhanced transparency,and lack of scattering and sedimentation are advantageous features for vat photopolymerization processes,whereas the absence of particulates reduces clogging problems at the nozzle for extrusion-based processes.Simultaneously,preceramic polymers and geopolymers have some limitations in terms of the range of ceramic compositions that can be obtained;sol-gel solutions are intrinsically unstable,whereas printed objects suffer from drying issues.Nevertheless,we successfully produced high-quality parts using a variety of additive manufacturing techniques,some of which(e.g.,volumetric additive manufacturing)have been proposed for the fabrication of ceramic components for the first time.展开更多
基金supported by the Natural Science Foundation of Shandong Province (ZR2020KE033,ZR2020ME051,ZR2019BEM013,ZR2021ME253)the Shandong Science and Technology Program (2021TSGC1122)+1 种基金the Shandong Postdoctoral Innovation Foundation (201903069)the Zibo Key Research and Development Project (2021SNPT0004,2021SNCG0076)。
文摘High-performance solid oxide fuel cell(SOFC) is in urgent need of high-quality electrolyte powders with high reactivity and chemical uniformity.Here,8 mol% Y_(2)O_(3) doped ZrO_(2)(YSZ) nano-powders were synthesized by an improved solid-state reaction method at ambient temperature,and were applied to the fabrication of SOFC electrolytes.YSZ nano-powders show average grain sizes of ^(2)0 nm and high dispersibility,which is comparable with or even better than some other chemical methods.Benefitting from their high reactivity,dense YSZ electrolytes(relative density of 97.9%) can be obtained at a relatively low sintering temperature of 1400℃.The optimized electrical conductivity reaches up to a high value of0.034 S/cm at 800 0C in air.The anode supported single cell with the construction of Ni-YSZ/YSZ/Sm_(0.2)Ce_(0.8)O_(2-δ)(SDC)/La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3-δ)(LSCF) exhibits the peak power density of 0.827 W/cm^(2) at800℃ while taking wet H_(2) as fuels and ambient air as oxidants.
基金supported by the National Natural Science Foundation of China(Nos.52302100 and 52402125)the Natural Science Foundation of Shandong Province(Nos.ZR2023ME140 and ZR2022QE024)+2 种基金the Youth Innovation Team Program in Colleges of Shandong Province(No.2023KJ144)the Innovation Capacity Improvement Project of Small and Medium-Sized Technology-Based Enterprise of Shandong Province(No.2024TSGC0540)the Key Laboratory of High-Temperature Electromagnetic Materials and the Structure of MOE,Wuhan University of Science and Technology(No.KB202405).
文摘To address the growing demand for radar and infrared stealth materials in complex application scenarios,this study develops an integrated multifunctional composite through a vacuum impregnation process that combines SiCN ceramics,porous ceramics,and phase change materials(PCMs).The unmodified SiCN ceramic,as a standalone component,exhibits a minimum reflection loss(RL_(min))of-14.91 dB,demonstrating its intrinsic electromagnetic absorption capability.When integrated into the composite,the porous ceramic matrix optimizes impedance matching,synergistically enhancing the overall microwave absorption performance.The resulting composite achieves RL_(min) of-31.29 dB with an effective absorption bandwidth(EAB)covering 96%of the X-band(8.2-12.4 GHz).Furthermore,the PCM embedded within the pores utilizes its latent heat during phase transition to regulate temperature fluctuations.When subjected to heating at 90℃(exceeding the PCM solid-liquid transition temperature)for 42 min,the composite exhibits a temperature rise of only 16.5℃,maintaining a 36.6℃difference from the external thermal load.This special thermal buffering capability ensures stable thermal insulation and infrared stealth functions while improving the electromagnetic response stability of the material under dynamic thermal conditions.The proposed design strategy offers new insights for advancing multifunctional electromagnetic wave(EMW)absorbing materials with enhanced performance adaptability.
基金support from the China Scholarship Council(Grant No.201804910741).Y.Feng acknowledges the support from the China Scholarship Council(Grant No.201806220175).
文摘In this review,we summarize the research activities carried out by our research group at the University of Padova on the additive manufacturing of ceramics from liquid feedstocks.Particularly,we evaluate the use of preceramic polymers,geopolymers,and sol-gel solutions.We mainly focus on processing with liquid feedstocks because they have some advantages with respect to slurry-based feedstocks in which powders are present.Particularly,lower viscosity,enhanced transparency,and lack of scattering and sedimentation are advantageous features for vat photopolymerization processes,whereas the absence of particulates reduces clogging problems at the nozzle for extrusion-based processes.Simultaneously,preceramic polymers and geopolymers have some limitations in terms of the range of ceramic compositions that can be obtained;sol-gel solutions are intrinsically unstable,whereas printed objects suffer from drying issues.Nevertheless,we successfully produced high-quality parts using a variety of additive manufacturing techniques,some of which(e.g.,volumetric additive manufacturing)have been proposed for the fabrication of ceramic components for the first time.
