Sn_(0.95)Ta_(0.05)P_2O_7/PTFE复合电解质的制备及中温电性能

先采用固相法制备Sn0.95Ta0.05P2O7电解质样品,再与适量聚四氟乙烯(PTFE)进行复合合成了有机-无机复合电解质聚四氟乙烯/Sn0.95Ta0.05P2O7。XRD测试表明PTFE/Sn0.95Ta0.05P2O7复合电解质衍射图谱与焦磷酸锡的JCPDS标准衍射图谱卡立方相Sn P2O7(JCPDS 00-029-1352)相同,还可以看出复合后新增加了PTFE的衍射峰,表明Sn0.95Ta0.05P2O7和PTFE复合没有发生反应生成新物质。SEM图可以看出样品致密性良好。采用电化学工作站对样品的中温电性能(40~200℃)进行了研究。结果表明,Sn0.95Ta0.05P2O7/PTFE在160℃下,电导率达到最大值为:1.7×10-2S·cm-1。     

Mg_2Ni_(0.95)Sn_(0.05)-C_6H_6浆液体系储氢性能

研究了Mg_2Ni_(0.95)Sn_(0.05)和苯以及Mg_2Ni_(0.95)Sn_(0.05)氢化物与苯分别组成的浆液的储氢性能,通过研究不同温度下合金和氢化物对浆液吸氢速率的影响,发现氢化物比合金对浆液的反应速率的影响更为显著。温度对反应的影响特别明显,在反应釜中氢气压力为7 MPa,反应釜桨搅拌速度为500r·min~(-1),温度为513K时合金和氢化物分别和苯组成的浆液表现出最佳的吸氢性能,其最大吸氢量分别达到了5.87％(mass)和6.02％(mass)。添加Sn后的合金Mg_2Ni_(0.95)Sn_(0.05)对苯加氢到环己烷的转化有很好的选择性。     

Zr_(0.92)Mg_(0.08)O_(1.92)和Zr_(0.92)Y_(0.08)O_(1.96)固体电解质的制备及性能

采用固相合成法在1 650℃分别合成了Zr0.92Mg0.08O1.92和Zr0.92Y0.08O1.962种固体电解质,其相对密度分别为96.19%和95.12%。XRD分析表明在Zr0.92Mg0.08O1.92和Zr0.92Y0.08O1.96固体电解质中均含有立方固溶体相,SEM分析表明2种材料微观结构致密。采用交流阻抗法分别测定了Zr0.92Mg0.08O1.92及Zr0.92Y0.08O1.96固体电解质在1 000~1 600℃的电导率。结果表明:随着温度的升高,Zr0.92Mg0.08O1.92固体电解质的电导率不断增大,但Zr0.92Y0.08O1.96的电导率在1 400℃时达到最大值(7.24×10—2 S/cm),随后降低;在1 000~1 450℃,Zr0.92Y0.08O1.96的电导率高于Zr0.92Mg0.08O1.92,在1 500~1 600℃,Zr0.92Mg0.08O1.92的电导率高于Zr0.92Y0.08O1.96。分析得到Zr0.92Mg0.08O1.92和Zr0.92Y0.08O1.96在1 000~1 450℃温度区间的电导激活能分别为1.61和0.20eV,在1 450~1 600℃温度区间的电导激活能分别为0.55和0.85eV。     

新型复合阴极Sr_(0.95)Ti_(0.05)Co_(0.95)O_(3-δ)–Sm_(0.2)Ce_(0.8)O_(1.9)在中低温固体氧化物燃料电池中的性能

采用柠檬酸自蔓延燃烧法合成了Sr0.95Ti0.05Co0.95O3-δ(STC)阴极粉体和Sm0.2Ce0.8O1.9(SDC)电解质粉体,将STC与SDC粉体按质量比7:3混合得到复合阴极。通过X射线衍射(XRD)、直流四端子法和热膨胀仪表征了样品的化学相容性、电导率和热膨胀系数。XRD表明,STC在900℃能够得到立方纯钙钛矿结构,复合阴极STC-SDC在工作温度区间内具有很好的化学相容性;在650℃空气气氛下STC-SDC与SDC之间的界面极化阻抗仅为0.05Ω·cm2。制备了阳极支持型(Ni O-SDC│SDC│STC-SDC)单电池,在450~650℃范围内以湿润的H2(3%水蒸汽)为燃料气,空气为氧化剂测试了单电池的性能。结果表明:阳极支撑的单电池共烧1 350℃可以得到致密的电解质层和多孔的电极,而且650℃时单电池开路电压0.82V,最大输出功率为721 m W/cm2。结果预示,在以SDC为电解质的中低温固体氧化物燃料电池(IT-SOFC)中,STC-SDC是一个很有前途的复合阴极材料。     

溶胶凝胶法制备Ce_(0.8)Y_(0.15)M_(0.05)O_(2-δ)电解质材料及其性能研究

文章以Ce0.8Y0.15M0.05O2-δ(M=Fe、Co、Mg)为主要研究对象。通过红外、致密度分析、X射线衍射、扫描电镜、交流阻抗、热膨胀等测试方法对试样进行测试和分析,对实验得到的电解质粉及相应的电解质材料的性能进行表征。实验结果表明:溶胶-凝胶法经700℃煅烧成功制备出了单相立方萤石结构的超细粉末,具有良好的烧结活性。1300℃下烧结后相对密度达到97%以上。电导率的测试表明,电解质材料在中温范围有较高的电导率,其中,Ce0.8Y0.15Mg0.05O1.9在800℃时,电导率达到了0.0661 S/cm。     

La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3–δ)–Sm_(0.2)Ce_(0.8)O_(1.9)复合阴极的制备及性能表征

分别采用凝胶浇注法和甘氨酸–硝酸盐法制备La0.6Sr0.4Co0.2Fe0.8O3–δ(LSCF)粉体与Sm0.2Ce0.8O1.9(SDC)粉体,随后制备出不同比例的LSCF–SDC复合阴极。用X射线衍射分析粉体的化学稳定性,用扫描电子显微镜观察复合阴极的微观结构,在500～800℃范围内测量其热膨胀系数和电导率。采用丝网印刷法将LSCF–SDC涂覆在SDC电解质片上,在1100℃烧结4h。用交流阻抗法在600～800℃范围内测量不同成分的LSCF–SDC复合阴极和SDC电解质的交流阻抗谱。结果表明:LSCF和SDC粉体具有良好的化学相容性,烧结体具有多孔结构,LSCF–SDC复合阴极与SDC电解质可形成良好的接触界面。SDC的加入在降低阴极材料的热膨胀系数的同时还保持了其本身较高的电导率,在中温范围内,电导率达到500S/cm以上。复合阴极的极化电阻随着SDC的含量增加而减小,当SDC含量为30%时,复合阴极的极化电阻最小,在700℃空气中测试得到的界面电阻为0.32Ω·cm2。     

(1-x)(Mg0.95Mn0.05)_2TiO_4-xCaTiO_3陶瓷的微波介电性能研究

采用传统固相法制备了(1-x)(Mg_0.95Mn_0.05)_2TiO_4-xCaTiO_3微波介质陶瓷,研究CaTiO_3添加量对陶瓷体系物相组成、显微结构以及微波介电性能的影响。XRD分析结果表明,陶瓷样品以(Mg_0.95Mn_0.05)_2TiO_4为主晶相,以CaTiO_3和MgTiO_3作为次晶相存在陶瓷样品中。另外发现添加CaTiO_3能增加陶瓷的致密度,并在1325~1400℃下都能促进陶瓷的烧结。当CaTiO_3的添加量为x=0.12时,复合陶瓷在1375℃烧结4 h时具有最佳的微波介电性能:介电常数ε_r=20.26,品质因数Q×f=35125.9 GHz,τ_f=+2.7×10~(-6)/℃。     

复合电解质SrCe0.9 Yb0.1 O3-α-LiCl-KCl的制备及其中温电性能研究

选择具有优良质子导电性的SrCe0.9 Yb0.1 O3-α与碱金属盐共熔体LiCl-KCl进行复合.制备复合电解质SrCe0.9 Yb0.1 O3-α-LiCl-KCl所用的温度(420℃)比制备SrCe0.9 Yb0.1 O3-α的温度(1500℃)显著降低.X射线衍射结果表明SrCe0.9 Yb0.1 O3-α和LiCl-KCl复合没有发生反应生成新物质.采用电化学工作站研究了单一SCYb电解质和复合SCYb-LK电解质在各种气氛中400~600℃下的电导率.结果表明,温度为600℃时,复合SCYb-LK电解质在湿润氮气气氛中的电导率为8.6×10-2 S·cm-1,复合SCYb-LK电解质的活化能远低于单一SCYb电解质.H2/O2燃料电池性能测试表明SrCe0.9 Yb0.1 O3-α-LiCl-KCl在600℃最大输出功率密度为113 mW·cm-2,是SrCe0.9 Yb0.1 O3-α在700℃相同条件下的7倍.     

5mol% Al~(3+)掺杂的TiP_2O_7-TiO_2复合陶瓷的中温电性能研究

以三氧化二铝、二氧化钛和浓磷酸为基本原料,用传统的固相合成法合成了新型的固体电解质材料Al3+掺杂的Ti P2O7-Ti O2复合陶瓷(5mol%Al3+),对合成的复合陶瓷进行了红外光谱、激光粒度仪、XRD测定,并且测定了电导率随实验条件的变化规律。红外结果表明,在样品的结构式中存在Al-O键、P=O键和P-O-Al键等,激光粒度测试表面在一定范围内,粒径分布集中。电导率测试表明在100~300℃温度内,电导率随着温度的升高而增大,300℃时达到最大值7.1×10-4 S·cm-1。     

YBaCo_2O_(5+δ)阴极材料的微观结构和热膨胀及电性能(英文)

研究了层状钙钛矿钴氧化物YBaCo2O5+δ阴极材料的微观结构和热膨胀及电性能.结果表明:YBaCo2O5+δ极材料具有与Ce0.8Gd0.2O2-δ固体电解质相匹配的热膨胀性能,显示出良好的化学和结构稳定性.YBaCo2O5+δ在高温下表现为金属导电特性,100~800℃温度范围内的电导率σ=153~35 S/cm.通过扫描电子显微镜和电子能谱手段,研究了YBaCo2O5+δ/Ce0.8Gd0.2O2-δ复合阴极中离子-电子混合导电相的微观结构.     

A vibrational study of phase transitions in Fe2P2O7 and Cr2P2O7 under high‐pressures

The vibrational properties of synthetic iron diphosphate (Fe₂P₂O₇) and chromium diphosphate (Cr₂P₂O₇) are studied under high‐pressure conditions between ~22 and ~30 GPa, respectively. Each compound's structural response to pressure and pressure‐induced phase transitions are characterized. The chromium‐bearing sample shows coalescence of infrared bands occurring near 6 and 17 GPa: these may be associated with increases in the local symmetry of the P₂O₇ group. The iron sample undergoes a first‐order phase transition near ~9 GPa, and a possible phase transition near 5.5 GPa. At 9 GPa, the initially single, strong symmetric PO₄ stretching mode splits into four modes, and the sole asymmetric PO₄ stretching mode splits into two bands. These changes indicate the presence of multiple tetrahedral environments within a larger volume unit cell, and the relative frequencies of the split vibrations indicate a P₂O₇ environment with a markedly narrowed P–O–P angle. The difference between the behavior of the iron and chromium compounds is probably generated by the smaller iron ion producing a discontinuous decrease in the P–O–P angle at lower pressures than in the analogous chromium compound. Our results demonstrate that the dimerized P₂O₇ group remains stable under compression to over 20‐30 GPa at 300 K.     

Facile Synthesis of BiOBr/Bi2Sn2O7 Heterojunction Photocatalysts with Improved Photocatalytic Activities

BiOBr/Bi₂Sn₂O₇ heterojunction photocatalysts were successfully synthesized by treating hydrothermal as‐prepared Bi₂Sn₂O₇ nanoparticles with hydrobromic acid (HBr). Partial Bi₂Sn₂O₇ nanoparticles reacted with HBr to form the sheet‐like BiOBr, and Bi₂Sn₂O₇ nanoparticles distributed evenly on BiOBr sheets. BiOBr/Bi₂Sn₂O₇ photocatalysts treated with different concentrations of HBr solution were successfully obtained, and their structures, morphologies, optical, and visible light photocatalytic properties were characterized by XRD, DRS, PL, SEM, and TEM. The experimental results showed that the BiOBr/Bi₂Sn₂O₇ photocatalysts showed improved photocatalytic activity under visible light irradiation than pure Bi₂Sn₂O₇. The sample treated with 0.08 mol/L HBr solution shows the best visible light photodegradation performance of rhodamine B. In addition, the active species and photocatalytic mechanism were discussed in detail.     

Li2O-CuO-P2O5玻璃的电性能

本文采用一种新的成形工艺制备20Li2O-30CuO-50P2O5(摩尔比)玻璃,并在玻璃转变温度之上对样品进行了不同时间的热处理后测试了其电性能。结果发现,随热处理时间的延长电导率会出现峰值,且所有样品电导率与温度之间的关系都能很好地遵从Arrhenius关系,结合SEM、XPS和XRD分析,对这一现象作出了初步的解释。     

细化颗粒固相法合成锂离子电池正极材料LiNi_(0.80)Co_(0.15)Al_(0.05)O_2及其结构和电化学性能研究

利用超细旋转盘式砂磨机细化颗粒固相烧结法,合成锂离子电池正极材料Li Ni0.80Co0.15Al0.05O2。原料经过砂磨后,混合均匀,粒径达到纳米级。根据塔曼定理,混合均匀的微小粒径可以在相同的烧结温度下,提高烧结的强度。SEM、XRD分别表征NCA材料的颗粒形貌和晶形结构。结果显示,通过细化颗粒烧结后的样品具有良好的形貌和层状结构。CV法测试样品的氧化还原性能,电池测试系统测试样品的电化学性能。测试结果显示,经过细化颗粒,在720℃合成的NCA材料具有良好的层状结构,018/110峰分裂明显。样品的电化学性能优良,0.2C下,首次放电容量达到182 m Ah?g?1,30次循环后容量保持率99.9%。1C下,首次放电容量153 m Ah?g?1,100次循环后容量保持率92.6%。     

磷酸锆基陶瓷材料的制备与性能研究

利用共沉淀法制备了磷酸锆，用差热分析法（DTA）研究了Zr2P2O7的热稳定性情况，并进一步研究了烧结助剂的量、烧结温度等对其性能的影响。     

Enhancing emission intensity and thermal stability by charge compensation in Sr2Mg3P4O15:Eu3+

Charge compensation was the effective methods to enhance the luminescence properties of phosphors. In this paper, novel single‐phased orange light emitting Sr₂Mg₃P₄O₁₅:Eu³⁺ phosphors were prepared by solid state method. The phase purity and luminous characteristics were examined in detail. Meanwhile, three kinds of charge compensation methods (co‐doping the alkali metal R⁺ (R⁺ = Li, Na, and K), substituting Si⁴⁺ for P⁵⁺ and self‐compensation) were employed to solve the charge imbalance problem between Sr²⁺ and Eu³⁺. The results showed that emission intensity of Eu³⁺ was improved by 1.43 (Li⁺), 1.58 (Na⁺), 1.53 (K⁺), 1.61 (Si⁴⁺), and 1.30 (self) times than that of Sr_1.6Mg₃P₄O₁₅:0.40Eu³⁺, respectively, and there was no change in the emitting color simultaneously. Furthermore, as the temperature reached at 423 K, the emission intensity increased from 41.67% of Sr_1.6Mg₃P₄O₁₅:0.40Eu³⁺ to 55.69% (Li⁺), 61.62% (Na⁺), 58.98% (K⁺), 71.15% (Si⁴⁺), and 80.59% (self) of that at room temperature. The reasons of those phenomena were the reduction in ion vacancies caused by charge imbalance through the charge compensation process. The specific mechanisms were elaborated in detail. Overall, this research validated that the charge compensation strategies could be severed as the key method to improve the luminescence properties, especially the thermal stability of phosphor.     

聚丙烯/Mg2B2O5晶须复合材料的非等温结晶动力学研究

采用熔融共混法制备了Mg2B2O5晶须(MBOw)和经硼酸酯偶联剂(BE)改性后MBOw分别填充的聚丙烯(PP)基复合材料,通过光学显微镜分析研究了BE对MBOw表面性质的影响,用DSC法并结合莫志深方程研究了PP及其填充改性前后MBOw复合材料的非等温结晶动力学。结果表明,BE改性后的MBOw表面性质较改性前发生根本变化;莫志深方程能较好地描述PP及其复合材料的非等温结晶动力学,MBOw对PP具有异相成核的作用,加快了PP的结晶速率,且BE使MBOw的异相成核能力得到增强,更有利于PP结晶速率的提高。     

(Sn1-x,Ni2x)O2纳米颗粒膜的制备及半导体性能

为提高SnO2的半导体性能,以分析纯SnCl2.2H2O和NiCl2.6H2O为主要原料,控制不同n(Ni2+)/n(Sn2+),利用溶胶凝胶-浸渍提拉法制备了(Sn1-x,Ni2x)O2纳米颗粒膜及半导体元件。用XRD、AFM对样品的结构、形貌进行了分析,并测试了(Sn1-x,Ni2x)O2元件的半导体性能。结果表明,(Sn1-x,Ni2x)O2纳米颗粒膜表面椭球形颗粒排列致密,尺寸约30 nm,(Sn1-x,Ni2x)O2为金红石型结构,但Ni2+代替了SnO2晶格中的部分Sn4+,使其晶胞参数a轴长平均减小0.000 4 nm,c轴长平均减小0.000 3 nm;随n(Ni2+)/n(Sn2+)由0.006增大到0.03,(Sn1-x,Ni2x)O2的晶粒尺寸由约45 nm减小至约18 nm;随温度由30℃上升至150℃,n型(Sn1-x,Ni2x)O2半导体元件的电阻约减小至其10%,而纯净SnO2元件的电阻仅约减小至其15%;随n(Ni2+)/n(Sn2+)的增大,离子化杂质散射增强,(Sn1-x,Ni2x)O2内部载流子迁移率下降,元件在150℃左右的电阻也由4.8 kΩ增大至12.1 MΩ,提高了元件的半导体性能。