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具有Ruddlesden-Popper结构的杂化非本征铁电体(Ca_(1-x)Sm_(x))_(3)Ti_(2)O_(7)陶瓷的制备及其物理性能
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作者 MARCO Antonio López-Aguila 柳志旭 +2 位作者 王守宇 黄聪 刘卫芳 《天津师范大学学报(自然科学版)》 CAS 北大核心 2024年第2期19-25,共7页
为探究稀土离子掺杂对Ca_(3)Ti_(2)O_(7)物理性能的调控,采用固相反应法制备了Sm^(3+)掺杂的(Ca_(1-x)Sm_(x))_(3)Ti_(2)O_(7)(x=0,0.02,0.04)陶瓷样品,通过XRD、XPS、紫外-可见光吸收光谱以及第一性原理计算等方法对样品的晶体结构、... 为探究稀土离子掺杂对Ca_(3)Ti_(2)O_(7)物理性能的调控,采用固相反应法制备了Sm^(3+)掺杂的(Ca_(1-x)Sm_(x))_(3)Ti_(2)O_(7)(x=0,0.02,0.04)陶瓷样品,通过XRD、XPS、紫外-可见光吸收光谱以及第一性原理计算等方法对样品的晶体结构、光学性能、电学性能和磁学性能进行分析.结果表明:随着Sm^(3+)含量的增加,(Ca_(1-x)Sm_(x))_(3)Ti_(2)O_(7)的晶胞参数逐渐增大.Sm^(3+)掺杂导致氧空位减少,因此样品的漏电流随着Sm^(3+)掺杂量的增加而减小.同时,随着Sm^(3+)掺杂量的增加,样品的光学带隙呈现增大趋势.此外,第一性原理研究表明,Sm^(3+)掺杂可在体系中诱导出磁性能,进一步丰富了该材料的物理性能. 展开更多
关键词 (ca_(1-x)Sm_(x))_(3)ti_(2)o_(7)陶瓷 铁电性 氧空位 光学带隙 第一性原理
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Review and prospects on the low-voltage Na_(2)Ti_(3)O_(7) anode materials for sodium-ion batteries
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作者 Jun Dong Yalong Jiang +3 位作者 Ruxing Wang Qiulong Wei Qinyou An Xiaoxing Zhang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第1期446-460,I0011,共16页
Due to its low cost and natural abundance of sodium,Na-ion batteries(NIBs)are promising candidates for large-scale energy storage systems.The development of ultralow voltage anode materials is of great significance in... Due to its low cost and natural abundance of sodium,Na-ion batteries(NIBs)are promising candidates for large-scale energy storage systems.The development of ultralow voltage anode materials is of great significance in improving the energy density of NIBs.Low-voltage anode materials,however,are severely lacking in NIBs.Of all the reported insertion oxides anodes,the Na_(2)Ti_(3)O_(7) has the lowest operating voltage(an average potential of 0.3 V vs.Na^(+)/Na)and is less likely to deposit sodium,which has excellent potential for achieving NIBs with high energy densities and high safety.Although significant progress has been made,achieving Na_(2)Ti_(3)O_(7) electrodes with excellent performance remains a severe challenge.This paper systematically summarizes and discusses the physicochemical properties and synthesis methods of Na_(2)Ti_(3)O_(7).Then,the sodium storage mechanisms,key issues and challenges,and the optimization strategies for the electrochemical performance of Na_(2)Ti_(3)O_(7) are classified and further elaborated.Finally,remaining challenges and future research directions on the Na_(2)Ti_(3)O_(7) anode are highlighted.This review offers insights into the design of high-energy and high-safety NIBs. 展开更多
关键词 Sodium-ion batteries Low-voltage anode materials Na_(2)ti_(3)o_(7) Electrochemical performances Electrochemical mechanism
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Al_(2)O_(3)粒度对CA_(6)轻质陶瓷材料结构与性能的影响
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作者 申天姿 李文凤 +3 位作者 郭会师 曹金金 侯永改 杜娟 《硅酸盐通报》 CAS 北大核心 2024年第6期2250-2255,共6页
为研究Al_(2)O_(3)粒度对CA_(6)轻质陶瓷材料结构与性能的影响,本文以平均粒径分别为80、61、45和38μm的α-Al_(2)O_(3)为氧化铝源,以平均粒径为15μm的轻质碳酸钙为氧化钙源,采用发泡法结合原位烧成工艺,经1550℃保温5 h烧成后获得CA_... 为研究Al_(2)O_(3)粒度对CA_(6)轻质陶瓷材料结构与性能的影响,本文以平均粒径分别为80、61、45和38μm的α-Al_(2)O_(3)为氧化铝源,以平均粒径为15μm的轻质碳酸钙为氧化钙源,采用发泡法结合原位烧成工艺,经1550℃保温5 h烧成后获得CA_(6)轻质陶瓷材料,研究不同粒度的Al_(2)O_(3)原料对其物相组成、显微结构和物理性能的影响。结果表明:随着α-Al_(2)O_(3)粒度的减小,CA_(6)轻质陶瓷的线收缩率、体积密度和热导率逐渐变小,显气孔率增大,压缩强度呈先增大后减小的趋势。综合考虑,以平均粒径为45μm的α-Al_(2)O_(3)为氧化铝源所制试样的综合性能较佳,更能满足使用需求,其显气孔率、热导率和压缩强度分别为87.8%、0.149 W·m^(-1)·K^(-1)和0.29 MPa。 展开更多
关键词 ca_(6)轻质陶瓷材料 Al_(2)o_(3)粒度 物相组成 显微结构 压缩强度 热导率
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退火工艺对Ca_(3)Ti_(2)O_(7)陶瓷微结构及杂化非本征铁电性能的影响
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作者 王钥涵 陈大凯 +4 位作者 周创 蔡苇 高荣礼 翟梦玉 张凤圆 《材料科学与工程学报》 CAS CSCD 北大核心 2023年第6期958-967,共10页
Ca_(3)Ti_(2)O_(7)因其独特的铁电性来源和室温下优异的铁电性,成为目前最受关注的杂化非本征铁电体。本研究采用溶胶-凝胶法结合高温烧结制备了Ca_(3)Ti_(2)O_(7)陶瓷,研究了退火工艺(温度、时间和气氛)对其微结构、介电性和铁电性的... Ca_(3)Ti_(2)O_(7)因其独特的铁电性来源和室温下优异的铁电性,成为目前最受关注的杂化非本征铁电体。本研究采用溶胶-凝胶法结合高温烧结制备了Ca_(3)Ti_(2)O_(7)陶瓷,研究了退火工艺(温度、时间和气氛)对其微结构、介电性和铁电性的影响。研究结果表明:氮气气氛、850℃下对Ca_(3)Ti_(2)O_(7)陶瓷退火30 min可获得较为优异的铁电性;相对于未退火的Ca_(3)Ti_(2)O_(7)陶瓷,退火后陶瓷的TiO_(6)八面体的面外倾侧角有一定程度增加;不同气氛下的退火处理会产生氧空位,从而使Ca_(3)Ti_(2)O_(7)陶瓷的晶粒尺寸有一定程度增大;真空退火后的陶瓷具有相对较大的晶粒尺寸和较多的氧空位,使其表现出相对较高的介电常数;经过退火处理的Ca_(3)Ti_(2)O_(7)陶瓷的漏电流均高于未退火的样品;通过对Ca_(3)Ti_(2)O_(7)陶瓷在不同气氛下进行退火处理可显著提升其剩余极化强度,同时矫顽场强有一定程度增加,其中空气和真空气氛下退火样品的剩余极化强度为2.9~3μC/cm^(2),表现出优异的杂化非本征铁电性。 展开更多
关键词 ca_(3)ti_(2)o_(7)陶瓷 杂化非本征铁电性 退火气氛 氧八面体
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2D/2D超薄La_(2)Ti_(2)O_(7)/Ti_(3)C_(2)Mxene肖特基异质结用于高效光催化CO_(2)还原 被引量:2
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作者 王可 程淼 +7 位作者 王楠 张千一 刘懿 梁俊威 管杰 刘茂昌 周建成 李乃旭 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2023年第1期146-159,共14页
CO_(2)的过量排放造成了全球生态系统的失衡,如温室效应、海洋酸化和极端天气频发等.CO_(2)作为一种储量丰富且可循环利用的碳一资源,利用光催化技术将其催化转化为包括一氧化碳和甲烷在内的碳氢燃料,为上述问题提供了一个很有前景的解... CO_(2)的过量排放造成了全球生态系统的失衡,如温室效应、海洋酸化和极端天气频发等.CO_(2)作为一种储量丰富且可循环利用的碳一资源,利用光催化技术将其催化转化为包括一氧化碳和甲烷在内的碳氢燃料,为上述问题提供了一个很有前景的解决方案.纳米片作为典型的二维材料,其厚度一般低至100 nm.此外,二维材料具有较大的比表面积、可调谐的端基官能团、出色的光学性能以及较好的导电性和柔韧性,在光催化领域受到了广泛关注.在半导体材料中,钛酸镧(La_(2)Ti_(2)O_(7))具有优良的氧化还原能力和良好的稳定性和耐久性,但与其他半导体类似,La_(2)Ti_(2)O_(7)的宽带隙性质决定了其只能利用波长较短的光,这极大地限制了其对太阳光的利用.为了增强光吸收能力,降低光生载流子的复合,本文通过溶剂热法在La_(2)Ti_(2)O_(7)纳米片上负载薄层Ti_(3)C_(2)MXene纳米片,设计制备了二维/二维(2D/2D)La_(2)Ti_(2)O_(7)/Ti_(3)C_(2)Mxene肖特基异质结复合材料,并用于增强光催化CO_(2)还原性能.研究发现,当Ti_(3)C_(2)MXene的负载量为3 wt%时,CO和CH4的产率是物理混合的La_(2)Ti_(2)O_(7)和Ti_(3)C_(2)MXene的4.6倍和11.4倍.飞秒瞬态吸收光谱和X射线光电子能谱结果表明,La_(2)Ti_(2)O_(7)/Ti_(3)C_(2)Mxene较好的光催化CO_(2)还原反应性能归因于高效电荷载流子迁移率和两组分接触界面之间形成了肖特基异质结的协同作用.原位红外漫反射光谱观察到的反应中间产物、紫外光电子能谱计算得到的功函数和原子层级的密度泛函理论计算得到的吉布斯自由能和差分电荷密度揭示了该体系光催化CO_(2)还原的机理、光催化反应的路径和产物选择性的由来.相比于单独的La_(2)Ti_(2)O_(7)和物理混合的La_(2)Ti_(2)O_(7)和Ti_(3)C_(2)MXene,2D/2D La_(2)Ti_(2)O_(7)/Ti_(3)C_(2)Mxene肖特基异质结复合材料表现出增强的光催化CO_(2)还原性能.引入Ti_(3)C_(2)MXene形成平面间2D/2D的异质结结构可作为电荷转移通道并促进电荷的快速分离,形成的肖特基结能够有效地抑制光生电子的回流,同时降低了光催化CO_(2)还原的反应势垒,最终促进了光催化CO_(2)还原过程.综上,本文详细阐述了肖特基异质结构中光催化性能增强的机理机制,并为设计和制造用于转化和利用二氧化碳的光催化剂及其探究光催化转化机理提供借鉴. 展开更多
关键词 钛酸镧 ti_(3)C_(2)MXene 光催化Co_(2)还原 二维/二维 肖特基异质结
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Ca_(2-x)Sr_(x)MgSi_(2)O_(7):Eu^(3+)荧光粉的制备及光致发光性能研究 被引量:4
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作者 亢小红 马科学 +2 位作者 苗波波 毕胜军 蒋娟梅 《当代化工》 CAS 2023年第8期1844-1847,1852,共5页
采用高温固相法制备了Ca_(2-x)Sr_(x)MgSi_(2)O_(7):Eu^(3+)红色荧光粉,利用X射线衍射仪、荧光光谱仪等对样品进行分析表征,探究Eu^(3+)掺杂于Ca_(2-x)Sr_(x)MgSi_(2)O_(7)基质的光致发光性能。结果表明:Eu^(3+)的掺杂没有改变Ca_(2-x)S... 采用高温固相法制备了Ca_(2-x)Sr_(x)MgSi_(2)O_(7):Eu^(3+)红色荧光粉,利用X射线衍射仪、荧光光谱仪等对样品进行分析表征,探究Eu^(3+)掺杂于Ca_(2-x)Sr_(x)MgSi_(2)O_(7)基质的光致发光性能。结果表明:Eu^(3+)的掺杂没有改变Ca_(2-x)Sr_(x)MgSi_(2)O_(7)基体的晶体结构,Ca_(2-x)Sr_(x)MgSi_(2)O_(7):Eu^(3+)荧光粉在410nm光激发下最强发射峰位于580nm的红光,Eu^(3+)掺杂量为4%时发光强度最高,Ca_(2-x)Sr_(x)MgSi_(2)O_(7):Eu^(3+)荧光粉可用于补充白光LED所需要的红色部分。 展开更多
关键词 ca_(2-x)Sr_(x)MgSi_(2)o_(7):Eu^(3+) 光致发光 红色荧光粉 白光LED
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Ca_(3)Ti_(2)O_(7)杂化非本征铁电体的制备及其掺杂改性研究进展 被引量:1
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作者 陈大凯 蔡苇 +2 位作者 周创 吴红迪 符春林 《电子元件与材料》 CAS CSCD 北大核心 2021年第10期983-989,1027,共8页
具有R-P层状钙钛矿结构的Ca_(3)Ti_(2)O_(7)材料具有由氧八面体面内旋转和面外倾侧引起的杂化非本征铁电性,因其有望打破铁电性与磁性电子构型互斥的关系,实现室温强磁电耦合而受到广泛关注。综述了近年Ca_(3)Ti_(2)O_(7)杂化非本征铁... 具有R-P层状钙钛矿结构的Ca_(3)Ti_(2)O_(7)材料具有由氧八面体面内旋转和面外倾侧引起的杂化非本征铁电性,因其有望打破铁电性与磁性电子构型互斥的关系,实现室温强磁电耦合而受到广泛关注。综述了近年Ca_(3)Ti_(2)O_(7)杂化非本征铁电体的制备方法、工艺及其掺杂改性的最新进展,重点阐述并总结了A位、B位掺杂及A/B位共掺对Ca_(3)Ti_(2)O_(7)材料杂化非本征铁电性的影响规律及改性机理,并对Ca_(3)Ti_(2)O_(7)材料的未来研究方向进行了展望。 展开更多
关键词 ca_(3)ti_(2)o_(7) 杂化非本征铁电性 综述 掺杂 氧八面体
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Improve titanate reduction by electro-deoxidation of Ca_(3)Ti_(2)O_(7) precursor in molten CaCl_(2) 被引量:3
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作者 Dong Wang Sheng Pang +3 位作者 Chun-yue Zhou Yan Peng Zhi Wang Xu-zhong Gong 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2020年第12期1618-1625,共8页
The low O^(2-)diffusion rate in the electro-deoxidation of titanium containing compounds by either the OS process or the FFC process leads to a low reaction speed and a low current efficiency.In this study,Ca_(3)Ti_(2... The low O^(2-)diffusion rate in the electro-deoxidation of titanium containing compounds by either the OS process or the FFC process leads to a low reaction speed and a low current efficiency.In this study,Ca_(3)Ti_(2)O_(7) was used as a precursor to improve the reduction speed of titanium.Because of the greater number of"diffusion channels"created in cathode as Ca^(2+) liberates from Ca_(3)Ti_(2)O_(7) precursor in the electrodeoxidation process,the O^(2-)diffusion rate was improved significantly by using Ca_(3)Ti_(2)O_(7) instead of CaTiO3 as precursor.Parallel constant voltage electrolysis(3.2 V)confirms that Ca_(3)Ti_(2)O_(7) and CaTiO3 are reduced simultaneously because of their similar crystal structures.However,the reduction area of Ca_(3)Ti_(2)O_(7) spreads much faster than that of CaTiO3,indicating a difference in the O^(2-) diffusion rate.Constant voltage cyclic voltammetry(CV)and theoretical analysis of the crystal structure were also conducted to compare the differences between Ca_(3)Ti_(2)O_(7) and CaTiO3.The results indicate that using a precursor with a greater number of soluble cations,titanium reduction speed can be greatly improved in the electro-deoxidation process.Finally,a new electrolysis method for converting and recycling excess CaO from the Ca_(3)Ti_(2)O_(7) precursor was proposed. 展开更多
关键词 calcium titanate ca_(3)ti_(2)o_(7) molten calcium chloride solid-state reaction reaction speed
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Ce^(3+)和Y^(3+)掺杂对Ca_2MgSi_2O_7:Eu^(2+)荧光粉发光性能的影响 被引量:4
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作者 章少华 胡江峰 +1 位作者 王建军 谢冰 《材料导报》 EI CAS CSCD 北大核心 2010年第6期8-10,共3页
在还原气氛下,采用高温固相法合成了Ca2MgSi2O7:Eu2+,R3+(R3+=Ce3+,Y3+)系列荧光粉。结果表明,少量稀土离子的掺入没有改变晶体的物相结构。在Ca2MgSi2O7:Eu2+荧光粉中,Ce3+和Y3+的掺入对荧光强度的影响较大,且与掺杂元素、掺杂量相关... 在还原气氛下,采用高温固相法合成了Ca2MgSi2O7:Eu2+,R3+(R3+=Ce3+,Y3+)系列荧光粉。结果表明,少量稀土离子的掺入没有改变晶体的物相结构。在Ca2MgSi2O7:Eu2+荧光粉中,Ce3+和Y3+的掺入对荧光强度的影响较大,且与掺杂元素、掺杂量相关。当掺杂Ce3+和Y3+的量分别为0.007mol和0.05mol时,所得荧光粉在532nm处的发光强度分别是未掺杂时的127%和117%。结果表明,在Ca2MgSi2O7中Ce3+与Eu2+存在能量传递,Ce3+的加入显著敏化了Eu2+的发光,导致荧光强度的进一步提高;Y3+的掺杂可以使荧光粉的粒径减小,并导致基质中的电荷缺陷而敏化Eu2+发光,从而使荧光强度进一步提高。 展开更多
关键词 荧光粉 ca_2MgSi_2o_7:Eu^2+ CE^3+ Y^3+ 发光性能
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温度对Ca_(3)Ti_(2)O_(7)陶瓷铁电性能的影响
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作者 谷强 王守宇 +2 位作者 吴星星 刘慧兰 刘卫芳 《天津师范大学学报(自然科学版)》 CAS 北大核心 2022年第3期50-54,共5页
为了研究温度对Ca_(3)Ti_(2)O_(7)材料铁电性能的影响,采用固相反应法制备了Ca_(3)Ti_(2)O_(7)单相陶瓷材料.对样品进行XRD测试以表征其结构,并通过Rietveld精修处理证明所得Ca_(3)Ti_(2)O_(7)陶瓷材料为单相材料.在不同温度下对样品进... 为了研究温度对Ca_(3)Ti_(2)O_(7)材料铁电性能的影响,采用固相反应法制备了Ca_(3)Ti_(2)O_(7)单相陶瓷材料.对样品进行XRD测试以表征其结构,并通过Rietveld精修处理证明所得Ca_(3)Ti_(2)O_(7)陶瓷材料为单相材料.在不同温度下对样品进行铁电性能测试,电滞回线、位移电流曲线和漏电流随温度的变化规律表明,Ca_(3)Ti_(2)O_(7)单相陶瓷材料的铁电特性会受到漏电流的影响,且Ca_(3)Ti_(2)O_(7)陶瓷具有可反转二极管效应的电输运特性.最后尝试利用带电缺陷与电偶极子的相互作用模型对电输运特性进行解释. 展开更多
关键词 ca_(3)ti_(2)o_(7) 铁电性 漏电流 可反转二极管效应
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C_(3)N_(4)-Ti_(4)O_(7)-MoS_(2)复合催化剂界面效应增强电催化析氢性能 被引量:1
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作者 杜佳峰 赵江红 任军 《燃料化学学报》 EI CAS CSCD 北大核心 2021年第7期986-997,共12页
电催化水裂解是目前最有前景的制氢技术之一。二硫化钼(MoS_(2))作为最有前途的非贵金属电解水制氢催化剂之一,受有限的催化位点和弱电导率的困扰,迫切地需要被进一步优化。本文采用简单的水热方法构建了C_(3)N_(4)-Ti_(4)O_(7)-MoS_(2... 电催化水裂解是目前最有前景的制氢技术之一。二硫化钼(MoS_(2))作为最有前途的非贵金属电解水制氢催化剂之一,受有限的催化位点和弱电导率的困扰,迫切地需要被进一步优化。本文采用简单的水热方法构建了C_(3)N_(4)-Ti_(4)O_(7)-MoS_(2)异质催化剂,利用活性组分间的界面相互作用,实现了催化剂活性位点的高度暴露、表面电荷的再分布、氢吸附动力学和稳定性的优化,改进了MoS_(2)的电催化析氢性能。结果表明,界面效应赋予C_(3)N_(4)-Ti_(4)O_(7)-MoS_(2)催化剂优异的电催化活性,即300 mV的过电位下获得50 mA/cm2的电流密度以及较低的Tafel斜率(54 mV/dec),长达33 h的析氢反应后仍保持高的催化活性,其电催化析氢性能优于纯MoS_(2)。结果表明,界面效应作为一种合理改进MoS_(2)基电催化剂的策略,对开发新型高效制氢电催化剂的发展至关重要。 展开更多
关键词 电解水 二硫化钼(MoS_(2)) 氮化碳(C_(3)N_(4)) ti_(4)o_(7) 界面效应 析氢反应(HER)
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High temperature X-ray diffraction study of the formation of Na_(2)Ti_(3)O_(7) from a mixture of sodium carbonate and titanium oxide 被引量:1
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作者 Caroline Piffet Bénédicte Vertruyen +3 位作者 Frédéric Hatert Rudi Cloots Frédéric Boschini Abdelfattah Mahmoud 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2022年第2期210-218,共9页
Na2Ti3O7 has attracted much attention in the field of anode materials for Na-ion batteries thanks to its non-toxicity and very low working potential of 0.3 V vs Na0/Na+.Building a clearer picture of its formation from... Na2Ti3O7 has attracted much attention in the field of anode materials for Na-ion batteries thanks to its non-toxicity and very low working potential of 0.3 V vs Na0/Na+.Building a clearer picture of its formation from cheap Na_(2)CO_(3) and TiO_(2) starting materials is therefore of obvious interest.Here,we report new insights from an in-situ high temperature X-ray diffraction study conducted from room temperature to 800°C,complemented by ex-situ characterizations.We were thereby able to position the previously reported Na_(4)Ti_(5)O_(12) and Na_(2)Ti_(6)O_(13) intermediate phases in a reaction scheme involving three successive steps and temperature ranges.Shifts and/or broadening of a subset of the Na_(2)Ti_(6)O_(13) reflections suggested a combination of intra-layer disorder with the well-established ordering of successive layers.This in-situ study was carried out on reproducible mixtures of Na_(2)CO_(3) and TiO_(2) in 1:3 molar ratio prepared by spraydrying of mixed aqueous suspensions.Single-phase Na_(2)Ti_(3)O_(7) was obtained after only 8 h at 800°C in air,instead of a minimum of 20 h for a conventional solid-state route using the same precursors.Microstructure analysis revealed~15 mm diameter granules made up from rectangular rods of a fewmm length presenting electrochemical properties in line with expectations.In the absence of grinding or formation of intimate composites with conductive carbon,the specific capacity of 137 m Ah/g at C/5 decreased at higher rates. 展开更多
关键词 Formation mechanism High temperature XRD Na_(2)ti_(3)o_(7) Spray-drying synthesis Na-ion batteries
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钠离子电池层状负极材料Na_(2)Ti_(3)O_(7)的研究进展
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作者 文淑湘 王诗敏 +1 位作者 张晶晶 李世友 《功能材料》 CAS CSCD 北大核心 2021年第8期8052-8059,共8页
层状钛酸钠(Na_(2)Ti_(3)O_(7))材料因其工作电压低、结构稳定、成本较低、绿色环保等优点,逐渐成为钠离子电池负极材料研究热点之一。综述了Na_(2)Ti_(3)O_(7)负极材料的主要制备方法,从体积膨胀、相变、表面副反应等角度分析了其电化... 层状钛酸钠(Na_(2)Ti_(3)O_(7))材料因其工作电压低、结构稳定、成本较低、绿色环保等优点,逐渐成为钠离子电池负极材料研究热点之一。综述了Na_(2)Ti_(3)O_(7)负极材料的主要制备方法,从体积膨胀、相变、表面副反应等角度分析了其电化学性能衰减的主要原因,并介绍了氧空位引入、掺杂、表面修饰、形貌调控等改性方法,最后对Na_(2)Ti_(3)O_(7)负极材料未来的研究方向及发展趋势进行了展望。 展开更多
关键词 钠离子电池 层状钛酸钠 制备 衰减 改性
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Nd_(0.9)Ca_(0.1)Ba_2Cu_3O_(7-δ) 超导体的结构
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作者 赵芸 《安徽机电学院学报》 1998年第2期68-70,共3页
用固相反应法制备,并通过不同条件的热处理得到了一组不同氧含量的Nd0.9Ca0.1Ba2Cu3O7-δ样品。用XRD确定了预烧粉末的结构特征,发现其为(Nd,Ca,Ba)CuO3钙钛矿结构,较之典型立方钙钛矿(SrT... 用固相反应法制备,并通过不同条件的热处理得到了一组不同氧含量的Nd0.9Ca0.1Ba2Cu3O7-δ样品。用XRD确定了预烧粉末的结构特征,发现其为(Nd,Ca,Ba)CuO3钙钛矿结构,较之典型立方钙钛矿(SrTiO3)出现新的113峰,且晶胞参数相应增大了一倍。随着氧含量的增大,Nd0.9Ca0.1Ba2Cu3O7-δ的结构发生从四方到正交相变,并讨论了其结构与超导电性的关系。 展开更多
关键词 Nd_(0.9)ca_(0.1)Ba_2Cu_3o_(7-δ) 钙钛矿 结构相变
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超低温烧结陶瓷Ca_(2)V_(2)O_(7)-LiF的微波介电性能
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作者 韩如意 郑宇欣 李波 《功能材料》 CAS CSCD 北大核心 2022年第12期12033-12038,共6页
通过固相法制备了超低温烧结Ca_(2)V_(2)O_(7)-LiF微波介质陶瓷,系统研究了掺入LiF对Ca_(2)V_(2)O_(7)烧结温度和微波介电性能的影响。研究表明,掺入LiF会导致在烧结区间内产生熔点极低的液相,液相的物质传递作用将烧结温度从920℃大幅... 通过固相法制备了超低温烧结Ca_(2)V_(2)O_(7)-LiF微波介质陶瓷,系统研究了掺入LiF对Ca_(2)V_(2)O_(7)烧结温度和微波介电性能的影响。研究表明,掺入LiF会导致在烧结区间内产生熔点极低的液相,液相的物质传递作用将烧结温度从920℃大幅降低至550℃。在最佳烧结温度550℃下,LiF不会与Ca_(2)V_(2)O_(7)反应生成杂相,也不会改变Ca_(2)V_(2)O_(7)的三斜结构。但是高于550℃时LiF与Ca_(2)V_(2)O_(7)形成了少量Ca_(5)F(VO_(4))_(3)。掺入LiF形成的超低熔点液相有助于超低温烧结并得到较高的密度进而得到较高的Q×f值。掺杂3%(质量分数)LiF的Ca_(2)V_(2)O_(7)在550℃下烧结3 h具有最佳的微波介电性能:ε_(r)=11.83,Q×f=46,476 GHz,τ_(f)=-116.43×10^(-6)/℃。 展开更多
关键词 超低温微波介质陶瓷 ca_(2)V_(2)o_(7) LIF
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Enhanced red luminescence of Ca_(3)Si_(2−x)M_(x)O_(7):Eu^(3+)(M=Al,P)phosphors via partial substitution of Si^(4+) for applications in white light-emitting diodes 被引量:1
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作者 Yu-Hao Ma Xi Gao +3 位作者 Wen-Tao Zhang Zhen-Rui Yang Zhou Zhao Chen Qu 《Rare Metals》 SCIE EI CAS CSCD 2024年第2期736-748,共13页
A red-emitting phosphor Ca_(2.91)Si_(2)O_(7):0.09Eu^(3+) with partial Al^(3+)/P^(5+) substitution on Si^(4+) was synthesized via a simple solid-state method,and the effects of the introduction of the M^(3+/5+)(M=Al,P)... A red-emitting phosphor Ca_(2.91)Si_(2)O_(7):0.09Eu^(3+) with partial Al^(3+)/P^(5+) substitution on Si^(4+) was synthesized via a simple solid-state method,and the effects of the introduction of the M^(3+/5+)(M=Al,P)ions on the crystal structure and photoluminescence performance of Ca_(2.91)Si_(2−x)M_(x)O_(7):0.09Eu^(3+) phosphors were investigated.The X-ray diffraction(XRD),energy-dispersive X-ray spectroscopy(EDS),and X-ray photoelectron spectroscopy(XPS)results revealed that the structure of Ca_(3)Si_(2)O_(7) remained the same after the introduction of Al^(3+) and P^(5+) ions.The characteristic emission of Eu^(3+)-doped Ca_(3)Si_(2−x)M_(x)O_(7) phosphors exhibited two main peaks at 617 nm(red)and 593 nm(orange)under excitation at 394 nm,which originated from the^(5)D_(0)→^(7)F_(2)and^(5)D_(0)→^(7)F_(1) electron transitions of Eu^(3+) ions.After the partial substitution of Al^(3+) and P^(5+),the red emission intensities of the Ca_(2.91)Si_(2)O_(7):0.09Eu^(3+) phosphors were significantly enhanced by 1.88-and 1.42-fold,respectively,which is attributed to the crystal-field effect around Eu^(3+).Meanwhile,the luminescence intensities of the Ca_(2.91)Si_(1.96)Al_(0.04)O_(7):0.09Eu^(3+) and Ca_(2.91)Si_(1.94)P_(0.06)O_(7):0.09Eu^(3+) phosphors at 210℃ were 79.36%and 77.53%of those at 30°C,respectively,indicating their excellent thermal stability.Moreover,the as-prepared Ca_(2.91)Si_(1.96)Al_(0.04)O_(7):0.09Eu^(3+)and Ca_(2.91)Si_(1.94)P_(0.06)O_(7):0.09Eu^(3+) red-emitting phosphors were combined with a near-ultraviolet chip of 395 nm to fabricate red-light-emitting diode(LED)and white(w)-LED devices with excellent chromaticity features.In summary,Al^(3+)/P^(5+)-substituted Ca_(2.91)Si_(2)O_(7):0.09Eu^(3+) can serve as red-emitting phosphors for applications in w-LEDs. 展开更多
关键词 ca_(3)Si_(2)o_(7) Red-emitting phosphor Structure substitution Luminescence enhancement Crystal-field effect White light-emitting diode
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ZnO-B_(2)O_(3)玻璃对Li_(2)Zn_(3)Ti_(4)O_(12)-CaTiO_(3)复合陶瓷低温烧结及性能的影响
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作者 舒国劲 袁世逢 +4 位作者 庞锦标 窦占明 杨俊 刘凯 韩光学 《硅酸盐通报》 CAS 北大核心 2021年第10期3305-3310,共6页
采用传统固相反应法制备0.94Li_(2)Zn_(3)Ti_(4)O_(12)-0.06CaTiO_(3)(LZT-CT)复合陶瓷,采用高温熔融法制备ZnO-B_(2)O_(3)(ZB)玻璃;以ZB玻璃为烧结助剂,研究了添加不同质量分数(x=0.5%、1.0%、1.5%、2.0%和2.5%)的ZB玻璃对LZT-CT复合... 采用传统固相反应法制备0.94Li_(2)Zn_(3)Ti_(4)O_(12)-0.06CaTiO_(3)(LZT-CT)复合陶瓷,采用高温熔融法制备ZnO-B_(2)O_(3)(ZB)玻璃;以ZB玻璃为烧结助剂,研究了添加不同质量分数(x=0.5%、1.0%、1.5%、2.0%和2.5%)的ZB玻璃对LZT-CT复合陶瓷的烧结特性、物相组成、微观结构以及微波介电性能的影响。结果表明:ZB玻璃能有效地将LZT-CT复合陶瓷的烧结温度从1 175℃降低到875℃,并促进了LZT-CT复合陶瓷的致密化。当ZB玻璃掺量x≤2.5%时,LZT-CT复合陶瓷中除了LZT、CT相,没有出现其他新相。随着ZB玻璃添加量增加,复合陶瓷的体积密度、介电常数(εr)、品质因数(Q×f)均先增加后减小,谐振频率温度系数(τf)变化不大,在(-2.25~4.51)×10^(-6)/℃波动。当ZB玻璃掺量为2.0%时,LZT-CT复合陶瓷在875℃烧结2 h,获得最大体积密度(4.22 g/cm^(3))以及优异的微波介电性能,εr=23.9,Q×f=58 595 GHz,τf=-0.14×10^(-6)/℃。 展开更多
关键词 Zno-B_(2)o_(3)玻璃 0.94Li_(2)Zn_(3)ti_(4)o_(12)-0.06catio_(3)复合陶瓷 低温烧结 微波介电性能
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Zn_(0.15)Nb_(0.3)Ti_(0.55-x)(Co_(1/3)Nb_(2/3))_(x)O_(2)陶瓷的微波介电性能研究
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作者 张文娟 《电子元件与材料》 CAS CSCD 北大核心 2021年第2期144-149,共6页
采用固相烧结法制备Zn_(0.15)Nb_(0.3)Ti_(0.55-x)(Co_(1/3)Nb_(2/3))_(x)O_(2)(x=0,0.05,0.15,0.25,0.35,0.4,0.45,0.55)陶瓷,研究了(Co_(1/3)Nb_(2/3))^(4+)取代Ti^(4+)对陶瓷的物相、微观形貌和微波介电性能的影响。实验结果表明,当(... 采用固相烧结法制备Zn_(0.15)Nb_(0.3)Ti_(0.55-x)(Co_(1/3)Nb_(2/3))_(x)O_(2)(x=0,0.05,0.15,0.25,0.35,0.4,0.45,0.55)陶瓷,研究了(Co_(1/3)Nb_(2/3))^(4+)取代Ti^(4+)对陶瓷的物相、微观形貌和微波介电性能的影响。实验结果表明,当(Co_(1/3)Nb_(2/3))^(4+)取代量x≤0.05时,Zn_(0.15)Nb_(0.3)Ti_(0.55-x)(Co_(1/3)Nb_(2/3))_(x)O_(2)陶瓷表现出纯的金红石Zn_(0.15)Nb_(0.3)Ti_(0.55)O_(2)相;当(Co_(1/3)Nb_(2/3))^(4+)取代量x>0.15时,有第二相ZnTiNb_(2)O_(8)和ZnNb_(2)O_(6)生成。陶瓷的Q×f值随x的增大而提高,介电常数(ε_(r))和谐振频率温度系数(τ_(f))则随ZnTiNb_(2)O_(8)和ZnNb_(2)O_(6)的增多而逐渐降低。当x=0.4时,Zn_(0.15)Nb_(0.3)Ti_(0.55-x)(Co_(1/3)Nb_(2/3))_(x)O_(2)陶瓷在1075℃下烧结获得最佳的微波介电性能:ε_(r)=35.44,Q×f=25862 GHz(f=5.8 GHz),τ_(f)=5.2×10^(-6)/℃。 展开更多
关键词 微波介质陶瓷 Zn_(0.15)Nb_(0.3)ti_(0.55-x)(Co_(1/3)Nb_(2/3))_(x)o_(2) 掺杂 介电性能 LTCC
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Dy^(3+)、Tm^(3+)共掺杂Ca2MgSi2O7的发光特性 被引量:4
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作者 胡莲莲 艾尔肯·斯地克 +2 位作者 万英 苏晓娜 王琇 《发光学报》 EI CAS CSCD 北大核心 2018年第7期948-954,共7页
采用高温固相法合成了系列Ca_2MgSi_2O_7∶Dy^(3+),Tm^(3+)发光材料。对样品进行了XRD结构表征,测量了激发光谱、发射光谱、色温和荧光寿命。研究结果表明,Ca_2MgSi_2O_7∶Tm^(3+)在355 nm激发下显示出蓝色发光,在CIE1931中的色坐标为x=... 采用高温固相法合成了系列Ca_2MgSi_2O_7∶Dy^(3+),Tm^(3+)发光材料。对样品进行了XRD结构表征,测量了激发光谱、发射光谱、色温和荧光寿命。研究结果表明,Ca_2MgSi_2O_7∶Tm^(3+)在355 nm激发下显示出蓝色发光,在CIE1931中的色坐标为x=0.165 9,y=0.082 2,色纯度为89%。通过Dy^(3+)和Tm^(3+)的叠加激发谱带激发,即在349,353,365 nm激发下,Ca_2MgSi_2O_7∶Dy^(3+),Tm^(3+)显示出青白、冷白和暖白光,相关色温值分别为5 193,9 672,4 685 K。300~500 nm区域间可以有效地激发Ca_2MgSi_2O_7∶Dy^(3+),Tm^(3+),并在400~600 nm之间产生蓝光和黄光复合产生的白光,表明该体系可用作白光LED的发光材料。 展开更多
关键词 ca_(2)MgSi_(2)o_(7)∶Dy^(3+) Tm^(3+)荧光粉 光致发光 白光LED 叠加激发谱带
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Cyan-green-emitting Ca_(3)Sc_(2)Si_(3)O_(12):Ce^(3+)transparent ceramics:A promising color converter for high-brightness laser lighting 被引量:4
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作者 Huajun Wu Hao Wu +3 位作者 Guo-Hui Pan Liangliang Zhang Zhendong Hao Jiahua Zhang 《Journal of Advanced Ceramics》 SCIE EI CAS CSCD 2023年第9期1731-1741,共11页
Transparent phosphor ceramics have received increasing attention for high-brightness laser lighting,but commercially available phosphor ceramics are currently mainly limited to yellow YAG:Ce and green LuAG:Ce garnets,... Transparent phosphor ceramics have received increasing attention for high-brightness laser lighting,but commercially available phosphor ceramics are currently mainly limited to yellow YAG:Ce and green LuAG:Ce garnets,leaving a“cyan cavity”which is an obstacle to realizing full-color lighting.Achieving new phosphor ceramics capable of filling the cavity is a challenge.Herein,for the first time,cyan-green-emitting Ca_(3)Sc_(2)Si_(3)O_(12):Ce^(3+)(CSS:Ce)transparent ceramics have been successfully developed by two-step sintering technique under vacuum.The as-prepared CSS:Ce ceramics present high relative density of 99.7%and optical transmittance of 71%in the cyan-green spectral region.It exhibits an efficient band emission peaking at 504 nm(under 450 nm excitation)with internal/external quantum efficiency of 91%/62%.Furthermore,it has excellent thermal stability with a thermal quenching temperature(T_(0.5))of 838 K,approximately 100 K higher than that of LuAG:Ce ceramics(738 K).In addition,the CSS:Ce ceramics can withstand blue laser density of 45.6 W/mm^(2)and meanwhile generates cyan-green light with a forward luminous flux of 813 lm and forward luminous efficacy of 162 lm/W.The CSS:Ce transparent ceramics exhibit excellent luminescence performance comparable to the commercial LuAG:Ce ceramics and could be a highly promising color converter for high-brightness laser lighting. 展开更多
关键词 transparent ceramics color converter laser lighting garnet ca_(3)Sc_(2)Si_(3)o_(12)(CSS)
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