以LiCoO2为阴极的全固态薄膜锂电池的研究

采用射频磁控溅射技术制备了非晶态和不同取向的多晶LiCoO2薄膜,利用XRD和SEM研究了不同温度退火后LiCoO2薄膜的结构和形貌.以具有不同结构的LiCoO2薄膜为阴极、含氮磷酸锂薄膜为电解质以及金属锂薄膜为阳极,成功地制备了电化学性能不同的全固态薄膜锂电池.由电化学研究结果表明,LiCoO2薄膜的结构和多晶取向决定了薄膜电池的电化学性能.采用具有一定取向的多晶LiCoO2薄膜制备的全固态薄膜锂电池具有最佳的性能,稳定放电容量达到55.4μAh/cm2μm,充放电循环次数超过450次.     

Si(100)衬底上Mg_(0.33)Zn_(0.67)O薄膜的结构及光学性能

采用射频磁控溅射法在Si(100)衬底上制备了Mg_(0.33)Zn_(0.67)O薄膜,研究了Mg_(0.33)Zn_(0.67)O薄膜的结构和光学性能。结果表明,Si(100)衬底上Mg_(0.33)Zn_(0.67)O薄膜呈六方纤锌矿结构,薄膜沿c方向取向生长,且c轴方向晶格增大0.03 nm。薄膜呈现优异的半导体特性,激子吸收峰位于297 nm,禁带宽度约为4.3 eV。薄膜平均粒径约为20 nm。薄膜在深紫外激发下的荧光发射位于368 nm。     

射频磁控溅射法制备薄膜电池电极的计算机模拟初步

计算机模拟仿真射频磁控溅射实验制备薄膜及离于电池电极,研究了在特定实验条件下薄膜的生长过程,并分析了影响薄膜生长的部分因素。     

(Ni0.8Zn0.2Fe2O4)epoxy-PZT双层膜中的磁电效应

讨论了Ni0.8Zn0.2Fe2O4(NZFO)与锆钛酸铅(PZT)的双层膜结构样品的磁电(ME)效应.NZFO粉料由溶胶-凝胶法制成,再经900℃热压,并高温烧结.在该双层膜中测量到了很强的磁电相互作用.发现横向的磁电效应比纵向效应大一个数量级,并且随NZFO烧结温度的提高而增加.当烧结温度从950℃上升到1380℃时,横向ME电压系数(αE)的最大值变化范围为25.6 mV Am-2≤αE≤199.6 mV Am-2.理论分析显示NZFO-PZT双层膜样品中ME效应源于NZFO与PZT之间相对良好的磁电耦合.     

重电子金属CeCu5.8 M0.2(M=Ni,Zn,Cd) 低温物性的比较

研究了不同元素等量掺杂下重电子金属CeCu5.8M0.2(M=Ni,Zn,Cd)低温电阻、比热容和磁化率随温度的变化关系.分析讨论了掺杂元素M(M=Ni,Zn,Cd)的磁性、价态及原子尺寸对近藤温度Tk、相干温度(即电阻极大值的温度TRmax)、每个Ce离子在较高温度时的平均磁矩μB以及在温度降低时被传导电子自旋屏蔽过程的影响.     

沉积温度、膜厚对Ce_(0.8)Gd_(0.2)O_(2-δ)薄膜的微结构和电导率影响

采用脉冲激光沉积法在MgO(100)单晶衬底上制备了Ce0.8Gd0.2O2-δ(CGO)系列薄膜,沉积温度与膜厚对CGO/MgO薄膜的微结构及离子电导率的影响分别被研究.X-ray衍射(2θ-ω线扫描,ω-摇摆曲线,(-扫描)测量显示,随着沉积温度的升高,CGO薄膜的微结构由多晶薄膜演变到外延膜.对沉积在730℃的CGO薄膜(510nm)中较大的离子电导归因于薄膜中较小的晶界密度.对高质外延的CGO薄膜(沉积730℃),随着膜厚的减小,其快速减小的激活能及增大的离子电导可解释为CGO/MgO界面平面的应变态和氧空位的无序分布所致.我们的结果表明,为获得高离子电导的CGO薄膜,最佳的沉积温度和膜厚是需要考虑的.     

蓝宝石衬底SnO2:Sb薄膜的制备及结构和光致发光性质

用射频磁控溅射法在蓝宝石(0001)衬底上制备出锑掺杂的氧化锡(SnO2:sb)薄膜.对制备薄膜的结构和发光性质进行了研究.制备样品为多晶薄膜,具有纯SnO2的四方金红石结构.室温条件下对样品进行光致发光测量,在334 nm附近观测到紫外发射峰,并对SnO2:Sb的光致发光机制进行了研究.     

Si(001)基片上反应射频磁控溅射ZnO薄膜的两步生长方法

利用反应射频磁控溅射技术，采用两步生长方法制备了ZnO薄膜，探讨了基片刻蚀时间和低温过渡层沉积时间对ZnO薄膜生长行为的影响.研究结果表明，低温ZnO过渡层的沉积时间所导致的薄膜表面形貌的变化与过渡层在Si(001)表面的覆盖度有关.当低温过渡层尚未完全覆盖基片表面时，ZnO薄膜的表面岛尺度较小、表面粗糙度较大，薄膜应力较大；当低温过渡层完全覆盖Si(001)基片后，ZnO薄膜的表面岛尺度较大、表面粗糙度较小，薄膜应力较小.基片刻蚀时间对薄膜表面形貌的影响与低温过渡层的成核密度有关.随着刻蚀时间的增加，ZnO薄膜的表面粗糙度逐渐下降，表面形貌自仿射结构的关联长度逐渐减小. 关键词： ZnO薄膜 反应射频磁控溅射 两步生长 形貌分析     

薄膜结构对Si／SiO2 I-V特性的影响

用射频磁控溅射法制备了3种结构的Si／SiO2纳米薄膜，测定了薄膜的I-V特性．实验结果分析表明，薄膜结构是影响其FV特性的主要因素．     

Cu_2O/C_(60)梯度薄膜的制备

功能梯度材料应用前景广阔 ,特别在 ICF研究中 ,梯度靶是一种重要的基础 -基准靶。以Cu2 O和 C60 为原料 ,用真空蒸镀法在石英基底上制备了 Cu2 O/C60 梯度薄膜 ,并用 XPS,AFM,紫外光谱仪对其成份分布、表面形貌、紫外吸收谱进行了测试。测量结果表明 ,薄膜的组成沿厚度方向呈连续梯度变化 ,符合梯度功能材料的变化规律     

新型锂离子电池正极材料LiMPO_4(M=Fe,Mn)的谱学和电化学研究

采用固相反应与液相反应,合成了新型锂离子电池正极材料LiMPO4(M=Fe,Mn)。粉末X光衍射表明材料均为纯相。对材料的显微拉曼光谱和红外光谱进行了研究和指认。循环伏安研究表明,含锂磷酸盐是一类有潜力的锂离子电池正极材料。     

Structural and electrochemical investigation of LiNi0.8Co0.2 − x M x O2 (M = Al, Al+Mg, Al+Mg+Fe) synthesized by solid-state method

Lithium nickel cobalt oxide materials doped with Al, Mg, and Fe were synthesized by solid-state reaction at 800 °C for 18 h to study the effects of adding transition and nontransition metals to the structure. Crystalline compounds were obtained as revealed by powder X-ray diffraction (XRD). Energy dispersive analysis of X-rays (EDAX) was used to determine the elemental ratio of all the samples. Impedance measurements showed that all samples have decreasing conductivities at higher temperatures and gave negative activation energies. The addition of nontransition metals actually decreased the conductivities of the materials.     

高性能的钛掺杂O3相O3-Na1-xCr1-xTixO2(x=0, 0.03, 0.05)用于钠离子电池正极材料的研究

本文通过凝胶热聚合路线合成了层状的O3相正极材料Na_1-xCr_1-xTi_xO₂(x=0, 0.03, 0.05),采用X射线衍射、扫描电子显微镜来分析其晶体结构和微观形貌. 研究发现,适量的钛掺杂有助于形成更均匀的颗粒并且会改变样品的颜色. 作为钠离子电池正极材料,Na//Na_0.97Cr_0.97Ti_0.03O₂具有非常高的库伦效率(首次高于96%),并且在2.0-3.6 V的电化学窗口下,用0.2 C的倍率循环100次,只有4%的容量衰减;在32 C倍率下有110 mAh/g的比容量.     

纳米MFe2O4（M=Ni,Zn）氧化物表面的光电子能谱

采用草酸共沉淀法制备了纳米MFe2O4（M=Ni,Zn）立方尖晶石粉体,分别用XRD、XPS等手段对所合成样品的相结构、表面元素状态进行了表征。Fe2p、O1s的XPS分析表明,氧化物表面存在Fe2＋及吸附态氧物种,氧空位的存在是形成反式尖晶石结构所致。     

Terahertz time-domain spectroscopy and optical properties of AM2O8 (A=Zr,Hf and M=W,Mo)

Terahertz time domain spectroscopy and optical properties of cubic ZrW₂O₈ and HfW₂O₈, and trigonal ZrMo₂O₈ and HfMo₂O₈ have been studied for the first time. It is shown that α-ZrW₂O₈ and α-HfW₂O₈ exhibit absorption peaks around 1.23 THz (41 cm^?1) and 1.18 THz (39.5 cm^?1), respectively, whereas no corresponding absorptions are observed for trigonal ZrMo₂O₈ and HfMo₂O₈. These external modes are suggested to originate from the librational and/or translational motions of the linked ZrO₆/HfO₆ and WO₄ polyhedra and to contribute to the negative thermal expansion of α-ZrW₂O₈ and α-HfW₂O₈. The absorption coefficients and refractive indices of these materials are derived from the transmission amplitudes of the THz field passing through the samples. The results suggest that cubic ZrW₂O₈ and HfW₂O₈ have the potential for THz filters or attenuators.     

In-situ X-ray microdiffraction analysis of local strain-field across the interface in a Pb(Zr0.52Ti0.48)O3/Ni0.8Zn0.2Fe2O4/Pb(Zr0.52Ti0.48)O3 tri-layered structure

We have performed a synchrotron X-ray microdiffraction to investigate the variation of the local strain-field across the interface in Pb(Zr_0.52Ti_0.48)O₃/Ni_0.8Zn_0.2Fe₂O₄/Pb(Zr_0.52Ti_0.48)O₃ (PZT–NZFO–PZT) tri-layered structure. In this study, we show that the in-plane lattice parameters of the NZFO lattice depend strongly on the piezoelectric strain of the PZT layer. This result explains that an electric-field-induced piezoelectric strain from the PZT layer is effectively transferred to the NZFO layer. Furthermore, the local strain persists within 20 μm away from the interface, inducing changes of magnetic responses via the inverse magnetostrictive effect.     

K7[P2Mo4W13M(H2O)O61]及其有机复合材料的合成及光谱研究

用降解法制得了Dawson结构铬、铁取代的磷钼钨酸钾,并将其与溴化(E)-N-丁基-4-(2-(4-二甲氨基苯基)乙烯基)吡啶反应制备了有机复合材料.通过元素分析和TG-DTA确定了配合物的组成分别为K7[P2Mo4W13M(H2O)O61](M=Cr(1),Fe(2))和(C19H25N2)6K3[P2Mo4W13MO62](M=Cr(3),Fe(4)).利用红外光谱、紫外-可见光谱、固体漫反射紫外-可见-近红外光谱、X射线光电子能谱以及荧光光谱对上述化合物进行了表征,并研究了复合材料中无机与有机组分间的相互作用及其荧光性质.     

Influence of fabrication processing on phase transition and electrical properties of 0.8Pb(Zr1/2Ti1/2)O3–0.2Pb(Ni1/3Nb2/3)O3 ceramics

The binary system of 0.8Pb(Zr_1/2Ti_1/2)O₃–0.2Pb(Ni_1/3Nb_2/3)O₃ ceramics were synthesized by conventional mixed oxide and columbite method. X-ray diffraction analysis demonstrated the coexistence of both the rhombohedral and tetragonal phases for the columbite prepared sample. Rhombohedral to tetragonal phase transition for columbite method was different compared with those of the mixed oxide method. The permittivity shows a shoulder at the rhombohedral to tetragonal phase transition temperature T_Rho–Tetra = 195 °C, and then a maximum permittivity (36,000 at 10 kHz) at the transition temperature T_m = 277 °C on ceramics prepared with the columbite method. However, piezoelectric coefficient (d₃₃) was measured to be 282 pC/N for the conventional method and higher than the columbite method. The results were related to the phase compositions and porosity of the ceramics.     

Ni/Pb(Zr,Ti)O3/TbFe2层状复合材料的谐振磁电特性研究

采用化学镀和黏接法制备层状磁电复合材料Ni/PZT/TbFe₂,研究其磁电性能及谐振频率随Ni层厚度的变化情况. 结果表明:Ni/PZT/TbFe₂层状磁电复合材料与其他结构的磁电性能不同,其一阶弯曲谐振峰值和纵向谐振峰值都很大. 随着Ni层厚度的增加,Ni/PZT/TbFe₂层状磁电复合材料的一阶纵向谐振峰值逐渐增大. 结合实验数据和理论计算值得出了材料的一阶弯曲谐振频率fr1和一阶纵向谐振频率f 关键词： 磁电效应 正磁致伸缩 负磁致伸缩 谐振频率     

Structural,elastic, electronic and thermal properties of M2SbP (M = Ti,Zr and Hf)

The structural, elastic, electronic and thermal properties of M₂SbP (M = Ti, Zr and Hf) were studied by means of a pseudo-potential plane-wave method based on the density functional theory within both the local density approximation and the generalised gradient approximation. The optimised zero-pressure geometrical parameters, i.e. the two unit cell lengths (a, c) and the internal coordinate (z), were in good agreement with available experimental and theoretical data. The effect of high pressure, up to 20 GPa, on the lattice constants shows that the contractions along the a-axis were higher than along c-axis. The anisotropic independent elastic constants were calculated using the static finite strain technique. Numerical estimations of the bulk modulus, shear modulus, Young's modulus, Poisson's ratio, average sound velocity and Debye temperature for ideal polycrystalline M₂SbP aggregates were performed in the framework of the Voigt–Reuss–Hill approximation. The calculated band structures show that all studied materials are electrical conductors. Analysis of the atomic site projected densities showed that the bonding is of covalent–ionic nature with the presence of metallic character. The density of states at the Fermi level is dictated by the transition metal d–d bands; the Sb element has little effect. Thermal effects on some macroscopic properties of M₂SbP were predicted using the quasi-harmonic Debye model, in which the lattice vibrations are taken into account. The variations of the volume expansion coefficient, heat capacity and Debye temperature with pressure and temperature in the ranges 0–50 GPa and 0–2000 K were obtained successfully.