Effect of preparation method for LSGMC5 on the performance of SSC-LSGMC5 composite cathodes

制备了Sm0.5Sr0.5CoO3(SSC)-La0.8Sr0.2Ga0.8Mg0.15Co0.05O3(LSGMC5)中温固体氧化物燃料电池(ITSOFC)复合阴极,其中LSGMC5用柠檬酸盐法和固相合成法合成。含有柠檬酸盐法合成的LSGMC5粉末的SSC-LSGMC5电极的氧还原电催化性能明显优于含固相合成法合成的LSGMC5的电极。随着焙烧温度的升高,柠檬酸盐法合成的LSGMC5粉末的颗粒变大,并致密化,导致相应SSC-LSGMC5复合电极与LSGMC5电解质的结合程度减弱以及氧还原电催化性能变差。复合阴极中柠檬酸盐法合成的LSGMC5粉末的最佳焙烧温度约为1 000℃。Sm0.5Sr0.5CoO3(SSC)-La0.8Sr0.2Ga0.8Mg0.15Co0.05O3(LSGMC5) composite cathodes for intermediate temperature solid oxide fuel cell(ITSOFC) were prepared.LSGMC5 powders were synthesized by the citrate method and the solid-state reaction.The oxygen reduction electrocatalysis activity of SSC-LSGMC5 electrodes containing LSGMC5 prepared by the citrate method was much higher than that containing LSGMC5 prepared by the solid-state reaction.With the increasing of the sintering temperature,the size of the LSGMC5 particles prepared by the citrate method increased and the particles were densification.The contact between the corresponding SSC-LSGMC5 composite electrode and LSGMC5 electrolyte was weakened,and the oxygen reduction electrocatalysis activity was reduced.The optimum sintering temperature for LSGMC5 powders prepared by the citrate method in the composite cathode was about 1 000 ℃.福建省科技攻关计划重点项目(2003H046);; 留学回国人员基金资

Preparation of Sm_(0.5)Sr_(0.5)CoO_3-La_(0.8)Sr_(0.2)Ga_(0.8)Mg_(0.15)Co_(0.05)O_3 Composite Cathodes Using Wet-chemistry Method and the Characterization of Their Properties

用湿化学法制备了Sm0.5Sr0.5CoO3(SSC)-La0.8Sr0.2Ga0.8Mg0.15Co0.05O3(LSGMC5)中温固体氧化物燃料电池复合阴极,其中SSC用甘氨酸-硝酸盐法合成,LSGMC5用柠檬酸盐法合成.XRD结果表明,甘氨酸-硝酸盐法制备的SSC在焙烧温度大于1223K即表现为单一的钙钛矿结构.随焙烧温度的升高,SSC粉末颗粒增大,导致相应电极与电解质的结合变差.复合电极的性能显著依赖于SSC粉末的焙烧温度,其中含1223K焙烧SSC粉末的电极表现出最小的欧姆电阻以及电极电阻.973K、氧气中、1A·cm-2电流密度下该电极的极化过电位仅为0.077V,远小于固相法合成的电极.Sm0.5Sr0.5CoO3(SSC)-La0.8Sr0.2Ga0.8Mg0.15Co0.05O3(LSGMC5) composite cathodes for intermediate temperature solid oxide fuel cells were prepared using wet-chemistry method. The SSC powders were prepared using the glycine-nitrate method and the LSGMC5 powders were synthesized using the citrate method. The XRD pattern of SSC powders calcined at temperatures higher than 1223 K corresponded to a desired perovskite structure. With the increase in calcining temperature, the size of the SSC particles increased, which leaded to a weak adhesion to the electrolyte for corresponding electrodes. The performance of the SSC-LSGMC5 composite electrodes depended strongly on the calcining temperature of SSC powders, and the electrodes based on SSC calcined at 1223 K exhibited the lowest ohmic resistance and polarization resistance. The overpotential at 973 K in oxygen under 1 A· cm-2 current density was as low as 0.077 V, which was much lower than that of electrodes prepared using solid-state reaction.福建省科技攻关计划重点项目(2003H046);; 留学回国人员基金资

Improving the performance of SOFCs cathode by using an interlayer based on the electrolyte material

利用在SSC-LSGMC5复合电极与LSGMC5电解质片之间加入与电解质相同材料的夹层的方法,提高了电极性能。不同温度下,在LSGMC5电解质片上印刷了厚度为2~5μm的LSGMC5薄膜,在薄膜上印刷了SSC-15%LSGMC5复合电极,并进行了表征。SEM结果表明:当夹层焙烧温度大于1 400℃时,夹层为致密结构,并与电解质完好地结合在一起,夹层与电极的结合程度远优于无夹层的电极|电解质界面。在700℃纯氧条件下,夹层(1 400℃焙烧)的引入,使电极极化电阻由0.38Ω.cm2减小至0.12Ω.cm2,1 A/cm2下的极化过电位由0.23 V减小至0.10 V。LSGMC5 interlayer was added between SSC-LSGMC5 composite electrode and LSGMC5 electrolyte flake,which had improved the cathode performance.The LSGMC5 interlayer was sintered on the LSGMC5 electrolyte flake at various temperatures,the thickness was about 2～5 μm.The SSC-15% LSGMC5 composite electrode was printed on the sintered interlayer and its performance was analyzed.SEM images exhibited that LSGMC5 interlayer well coated on the electrolyte was dense while the interlayer was sintered at a temperature higher than 1 400 ℃.The coating degree of the electrode｜interlayer interface sintered at high temperatures was better than that of the electrode｜electrolyte interface without an interlayer.The polarization resistance of cathode decreased from 0.38 Ω·cm~2 to 0.12 Ω·cm~2 and the polarization over-potential under 1 A/cm~2 decreased from 0.23 V to 0.10 V at 700 ℃ in oxygen by using an LSGMC5 interlayer calcined at 1 400 ℃.福建省科技攻关计划重点项目(2003H046);; 留学回国人员基金资助项

Preparation of Sm0.5Sr0.5CoO3-La0.8Sr0.2Ga0.8Mg0.15Co0.05O3 composite cathodes using wet-chemistry method and the characterization of their properties

Sm0.5Sr0.5CoO3(SSC)-La0.8Sr0.2Ga0.8Mg0.15Co0.05O3(LSGMC5) composite cathodes for intermediate temperature solid oxide fuel cells were prepared using wet-chemistry method. The SSC powders were prepared using the glycine-nitrate method and the LSGMC5 powders were synthesized using the citrate method. The XRD pattern of SSC powders calcined at temperatures higher than 1223 K corresponded to a desired perovskite structure. With the increase in calcining temperature, the size of the SSC particles increased, which leaded to a weak adhesion to the electrolyte for corresponding electrodes. The performance of the SSC-LSGMC5 composite electrodes depended strongly on the calcining temperature of SSC powders, and the electrodes based on SSC calcined at 1223 K exhibited the lowest ohmic resistance and polarization resistance. The overpotential at 973 K in oxygen under 1 A . cm(-2) current density was as low as 0.077 V, which was much lower than that of electrodes prepared using solid-state reaction

Effect of a La_(0.8)Sr_(0.2)Ga_(0.8)Mg_(0.15)Co_(0.05)O_3 interlayer synthesized by the citrate method on the cathode performance

考察了在Sm0.5Sr0.5CoO3(SSC)-La0.8Sr0.2Ga0.8Mg0.15Co0.05O3(LSGMC5)/LSGMC5界面中加入柠檬酸盐法合成的LSGMC5夹层对界面的影响。考察了含不同温度焙烧的LSGMC5夹层的SSC-LSGMC5/LSGMC5/LSGMC5组合的微观结构及电化学性能。当夹层焙烧温度高于1 623 K时,夹层与电极的结合优于无夹层的电极/电解质界面,具有大的两相界面面积及三相界面长度。制备的组合的氧还原性能依赖于夹层以及电极的焙烧温度,含有1 673 K烧结夹层、1 123 K焙烧电极的样品具有最高的活性。与含固相法制备的LSGMC5夹层的样品相比,采用含柠檬酸盐法制备的夹层的组合具有更小的欧姆电阻及更高的氧还原活性。The effect of the addition of a La_(0.8)Sr_(0.2)Ga_(0.8)Mg_(0.15)Co_(0.05)O_3(LSGMC5) interlayer synthesized by the citrate method into the Sm_(0.5)Sr_(0.5)CoO_3(SSC)-LSGMC5/LSGMC5 interface was studied.Microstructures and electrochemical performance of the SSC-LSGMC5/LSGMC5/LSGMC5 assembly with an LSGMC5 interlayer synthesized at various temperatures were studied.The bonding of electrode/interlayer interface was better than that of electrode/electrolyte interface without interlayer when the sintered temperature was higher than 1 623 K,showed a larger two-phase boundary area and three-phase boundary length.The performance of prepared assembly depended on the sintering temperature of both the interlayer and the electrode.The sample assembly with an interlayer sintered at 1 673 K and an electrode sintered at 1 123 K exhibited the highest performance.Compared with the assembly with an LSGMC5 interlayer synthesized by the solid-state reaction,assembly with an LSGMC5 interlayer synthesized by the citrate method showed a reduced ohmic resistance and improved activity for oxygen reduction.福建省科技攻关计划重点项目(2003H046);; 留学回国人员基金资助项

InP基MOEMS可调谐器件的梁变形模拟

InP基微光机电系统（MOEMS）可调谐器件的梁在实验中常出现弯曲变形的现象，其原因是在生长的时候，As原子进入InP梁，产生了内部梯度应力．使用有限元分析软件，建立了一种无须测量内部应力的模拟梁变形的方法．模拟了单臂梁和双臂梁的弯曲变形情况，理论与实验吻合．研究了As原子浓度和梁厚度对梁变形情况的影响，结果表明降低As原子浓度和增大梁厚度都有助于抑制梁的变形

一种长波长MOEMS可调谐滤波器的结构设计和分析

提出了一种微光机电系统（MoEMS）可调谐滤波器结构，该结构采用GaAs／AlGaAs作为下分布布拉格反射镜（DBR），GaAs和SiO_2／Si介质膜作为上DBR，空气作为腔．按照波分复用系统的性能要求对MOEMS可调谐滤波器各项参数，如带宽、峰值透射率、挠度和调谐速度等进行了分析和设计．研究了挠度和调谐速度与梁厚度、宽度、长度等参数的关系．结果表明挠度与长度成正方向变化，同梁厚度、宽度成反方向变化，而调谐速度与各参数的关系恰好相反

具有非均匀渐变界面DBR的光学特性分析

应用特征矩阵法研究了非均匀渐变界面Al_(0.9)Ga_(0.1)As/AlyGa_(1-y)As/GaAs/Al_xGa_(1-x)As DBR的光学特性.建立了非均匀渐变界面AlyGa1-yAs的折射率模型，并得到了渐变界面特征矩阵的解析解，通过特征矩阵法分别计算了突变GaAs/Al_(0.9)Ga_(0.1)As DBR和渐变DBR的反射谱和反射相移，分析了非均匀渐变层对DBR光学特性的影响，对渐变DBR，需要在DBR前面再增加一定厚度的非均匀渐变相位匹配层才能使整个DBR满足中心波长相位匹配条件，并通过光学厚度近似方法求出相位匹配层厚度

数值分析渐变DBR对垂直腔面发射激光器谐振腔模的影响

通过数值分析研究了含线性渐变层的Al_(0.9)Ga_(0.1)As/Al_yGa_(1-y)As/GaAs/Al_xGa_(1-x)As DBR的光学特性及其对VCSEL谐振腔光学特性的影响,建立了渐变型DBR渐变层厚度与折射率的关系,通过特征矩阵法计算了突变GaAs/Al_(0.9)Ga_(0.1)As DBR和渐变型DBR的反射谱和反射相移,分析了渐变层对DBR反射率和反射相移的影响.对渐变型DBR,要使VCSEL谐振腔满足中心波长相位匹配条件,还需要在DBR靠近谐振腔一侧的最前面增加一定厚度的渐变层,称为相位匹配层.通过计算,我们得到了使VCSEL谐振腔满足相位匹配条件时均匀层和相位匹配层的厚度