Searching for compatible electrolytes with Ni_(0.8)C_(00.15)Al_(0.05)LiO_(2-δ)(NCAL)electrodes that exhibit high ionic conductivity at low operational temperatures(<550℃)is crucial for advancing ceramics fuel cel...Searching for compatible electrolytes with Ni_(0.8)C_(00.15)Al_(0.05)LiO_(2-δ)(NCAL)electrodes that exhibit high ionic conductivity at low operational temperatures(<550℃)is crucial for advancing ceramics fuel cells(CFCs)research.In this work,the experimental and theoretical analyses demonstrate that the highly stable single-phase Gd_(3)Ga_(5)O_(12)(GGO)garnet structure,composed of Gd-O octahedrons and Ga-O tetrahedrons,provides more active sites for ion transport,resulting in enhanced peak power density(PPD)and stable open circuit voltage(OCV)at low operational temperatures.The unique internal garnet structure effectively reduces the interfacial impedance of the prepared fuel cell device,provides more active sites at triple-phase boundarie region,and increases the electrochemical stability.As a result,the constructed fuel cell device can deliver a superior peak power density of 770 mW/cm^(2)at 490℃.In addition,X-ray photoelectron spectroscopy,electrochemical impedance spectroscopy,and theoretical calculations further demonstrate electrolyte effectiveness of GGO,enabling stable an OCV even at a low temperature of 370℃under a H_(2)/air environment.This work contributes to a deeper understanding of the underlying mechanisms of a single-layer fuel cell device,which is essential for advancing this promising energy technology,even at a very low temperature of 370℃.展开更多
Ca3Sc2Si3O12:Ce3+ phosphors with single-phase were successfully synthesized by a gel-combustion method.Annealing atmosphere greatly affected the luminescent properties of the phosphor.The intensity of absorption band ...Ca3Sc2Si3O12:Ce3+ phosphors with single-phase were successfully synthesized by a gel-combustion method.Annealing atmosphere greatly affected the luminescent properties of the phosphor.The intensity of absorption band at 450 nm was greatly increased with a reducing atmosphere,which was very suitable as a color converter in white LED.The absorption at 243 and 311 nm was gradually enhanced with a stronger reducing atmosphere and a new absorption peak at 362 nm appeared in N2+H2 mixing gas.The emission intensit...展开更多
In this work,novel medium-entropy Ca_(3)(Co_(0.25)Zn_(0.25)Mg_(0.25)Cu_(0.25))_(2)SiV_(2)O_(12)(CZMC)ceramics with garnet structure were designed and synthesized based on the entropy effect.A small average atomic size...In this work,novel medium-entropy Ca_(3)(Co_(0.25)Zn_(0.25)Mg_(0.25)Cu_(0.25))_(2)SiV_(2)O_(12)(CZMC)ceramics with garnet structure were designed and synthesized based on the entropy effect.A small average atomic size difference was proven to be advantageous for the formation of a garnet-structured solid solution,as evidenced via X-ray diffraction(XRD)and Rietveld refinement results.The sintering temperature was effectively reduced due to an increase in the configurational entropy(ΔS_(config)).The dielectric constant(ε_(r))of the CZMC ceramics showed the opposite trend to that of the Raman shift at approximately 838 cm^(−1),whereas the variation in the quality factor(Q×f)was identical to that of the relative density but opposite to that of the full width at half maximum(FWHM)of the Raman spectra.Alternating current(AC)impedance spectroscopy revealed that the conductivity of the CZMC ceramics was affected mainly by the diffusion of thermally activated oxygen vacancies.The high activation energy further indicated that the low defect concentration in the sample contributed to reducing the dielectric loss of the ceramics.The B‒O bond had the strongest contribution to the total bond energy,thus playing an important role in manipulating the temperature coefficient of the resonant frequency(τ_(f))of the ceramics.Moreover,the V‒O bond significantly influenced theε_(r)and the Q×f of the CZMC ceramics.Finally,superior microwave dielectric properties(ε_(r)=10.89,Q×f=59,200 GHz,andτ_(f)=-9.6 ppm/°C)together with a high relative density of 95.4%were achieved at 1010°C.Therefore,extensive applications can be found in the field of millimeter wave communication for CZMC ceramics.展开更多
基金supported by the Jiangsu Fundamental Research Program(JSSCRC2021491)Ongoing Research Funding Program(ORF-2025-391)。
文摘Searching for compatible electrolytes with Ni_(0.8)C_(00.15)Al_(0.05)LiO_(2-δ)(NCAL)electrodes that exhibit high ionic conductivity at low operational temperatures(<550℃)is crucial for advancing ceramics fuel cells(CFCs)research.In this work,the experimental and theoretical analyses demonstrate that the highly stable single-phase Gd_(3)Ga_(5)O_(12)(GGO)garnet structure,composed of Gd-O octahedrons and Ga-O tetrahedrons,provides more active sites for ion transport,resulting in enhanced peak power density(PPD)and stable open circuit voltage(OCV)at low operational temperatures.The unique internal garnet structure effectively reduces the interfacial impedance of the prepared fuel cell device,provides more active sites at triple-phase boundarie region,and increases the electrochemical stability.As a result,the constructed fuel cell device can deliver a superior peak power density of 770 mW/cm^(2)at 490℃.In addition,X-ray photoelectron spectroscopy,electrochemical impedance spectroscopy,and theoretical calculations further demonstrate electrolyte effectiveness of GGO,enabling stable an OCV even at a low temperature of 370℃under a H_(2)/air environment.This work contributes to a deeper understanding of the underlying mechanisms of a single-layer fuel cell device,which is essential for advancing this promising energy technology,even at a very low temperature of 370℃.
基金supported by the Ministry of Science and Technology of China (2006CB601104,2006AA03A133)
文摘Ca3Sc2Si3O12:Ce3+ phosphors with single-phase were successfully synthesized by a gel-combustion method.Annealing atmosphere greatly affected the luminescent properties of the phosphor.The intensity of absorption band at 450 nm was greatly increased with a reducing atmosphere,which was very suitable as a color converter in white LED.The absorption at 243 and 311 nm was gradually enhanced with a stronger reducing atmosphere and a new absorption peak at 362 nm appeared in N2+H2 mixing gas.The emission intensit...
基金the Natural Science Foundation of Anhui Provincial Education Department(No.KJ2019A0054)the Anhui Provincial Natural Science Foundation(No.1608085ME92).
文摘In this work,novel medium-entropy Ca_(3)(Co_(0.25)Zn_(0.25)Mg_(0.25)Cu_(0.25))_(2)SiV_(2)O_(12)(CZMC)ceramics with garnet structure were designed and synthesized based on the entropy effect.A small average atomic size difference was proven to be advantageous for the formation of a garnet-structured solid solution,as evidenced via X-ray diffraction(XRD)and Rietveld refinement results.The sintering temperature was effectively reduced due to an increase in the configurational entropy(ΔS_(config)).The dielectric constant(ε_(r))of the CZMC ceramics showed the opposite trend to that of the Raman shift at approximately 838 cm^(−1),whereas the variation in the quality factor(Q×f)was identical to that of the relative density but opposite to that of the full width at half maximum(FWHM)of the Raman spectra.Alternating current(AC)impedance spectroscopy revealed that the conductivity of the CZMC ceramics was affected mainly by the diffusion of thermally activated oxygen vacancies.The high activation energy further indicated that the low defect concentration in the sample contributed to reducing the dielectric loss of the ceramics.The B‒O bond had the strongest contribution to the total bond energy,thus playing an important role in manipulating the temperature coefficient of the resonant frequency(τ_(f))of the ceramics.Moreover,the V‒O bond significantly influenced theε_(r)and the Q×f of the CZMC ceramics.Finally,superior microwave dielectric properties(ε_(r)=10.89,Q×f=59,200 GHz,andτ_(f)=-9.6 ppm/°C)together with a high relative density of 95.4%were achieved at 1010°C.Therefore,extensive applications can be found in the field of millimeter wave communication for CZMC ceramics.
