烧结助剂对Li1.3Al0.3Ti1.7(PO4)3固态电解质导电性能的影响

采用溶胶凝胶法制备了Li1.3Al0.3Ti1.7(PO4)3(LATP)固态电解质,研究了不同烧结助剂对LATP固态电解质离子电导率的影响.利用X射线衍射(XRD)、扫描电子显微镜(SEM)、电化学阻抗谱(EIS)等方法探究了样品的晶体结构、形貌特征以及离子导电性能.研究结果表明,虽然添加烧结助剂会产生少量二次相,仍...     

锂快离子导体Li3-2x(Al1-xTix)2(PO4)3的合成与表征

NASICON型正磷酸盐LiM2(PO4)3(M=Ti,Ge,Zr,Hf)是近来研究得比较深入的锂快离子导体.LiTi2(PO4)3难于烧结得到致密的LiT2(PO4)3陶瓷,且离子电导率很低,在298K时为8.260×10-8 S/cm,613K时为8.241×10-5 S/cm,而当以三价的Al3 离子经传统的固相烧结反应部分取代LiTi2(PO4)3中四价的Ti4 离子后,通过DSC、DTG、电化学阻抗与SEM测试表明,不仅能获得致密度高稳定的产物,而且烧结后得到的锂快离子导体Li3-x(Al1-xTix)2(PO4)3(X=1.0～0.55)体系在室温下的电导率有了巨大的提高.当X=0.85时,组分Li1.3Al0.3Ti1.7(PO4)3离子电导率最大,298K时为1.792×10-6S/cm和613K时为9.210×10-4S/cm.     

PEO-Li1.3Al0.3Ti1.7(PO4)3固态聚合物电解质的制备与特性

将实验室制备的Li1.3Al0.3Ti1.7(PO4)3与PEO根据不同EO/Li摩尔比,通过溶液浇铸法技术制备了锂离子导电的PEO-Li1.3Al0.3Ti1.7(PO4)3固态聚合物电解质(SPE)膜,真空干燥后经X射线衍射分析、红外(IR)测试、示差扫描量热分析(DSC)分析和电化学阻抗测试(EI)研究了其结构与电导率性能之间的关系.证实了在固态聚合物电解质PEO-Li1.3Al0.3Ti1.7(PO4)3体系中存在络合体,并且当EO/Li=16时,这种聚合物电解质活化能最低值为0.475 eV,电导率值最佳,即25℃为2.631×10-7S/cm,100℃为1.185×10-4S/cm.     

PEO-Li1.3Al0.3Ti1.7(PO4)3复合聚合物电解质的制备与电导率研究

将实验室制备的两种烧结型的Li1.3Al0.3Ti1.7(PO4)3盐与PEO/LiClO4复合,制得了PEO-LiClO4-Li1.3Al0.3Ti1.7(PO4)3复合聚合物电解质,测量了298～373K温度范围内的阻抗,得出这种体系的复合聚合物电解质的离子电导率在室温最高值为1.387×10-5S/cm,在373K时可达到1.378×10-3S/cm.     

锂离子电池正极材料磷酸钒锂的研究进展

磷酸钒锂是一种新型的锂离子电池正极材料,其电化学性能受合成方法及工艺条件的影响.介绍了Li3V2(PO4)3的结构特点及充放电过程的电化学特征.全面综述了采用固相反应法、溶胶-凝胶法及微波法等制备磷酸钒锂的研究现状,并比较了各种方法的利弊.     

溶胶凝胶法制备钠离子固态电解质Na3Zr2Si2PO12及其电导性能研究

采用溶胶凝胶法,探索了合成纯相Na3Zr2Si2PO12的条件,XRD分析表明前驱体中Na和P均过量10%时,在1050℃下烧结得到了纯相的Na3Zr2Si2PO12,而P不过量时,得到的产物中含有少量的ZrO2杂质。电化学阻抗谱测试表明Na和P均过量10%时,烧结得到的陶瓷片室温离子电导率达到了5.4×10-4S/cm,比P不过量时烧结得到样品的离子电导率(室温时为3.7×10-4S/cm)要高。进一步分析可知高温下P的挥发造成ZrO2杂质相的析出,从而使得离子电导率降低。与固相法相比,溶胶凝胶法需要的烧结温度更低,且制得的样品的离子传导性更好。     

尖晶石Li4Ti5O12-xFx的制备与电化学计量性能研究

为了改善尖晶石型Li4Ti5O12材料的电子电导率和离子导电性,许多研究者认为阳离子掺杂改性是较有效的途径之一。主要通过金属阳离子V5+,Mn4+,Fe3+,Al3+,Ga3+Co3+,Cr3+,Ni2+,Mg2+等取代锂位或者钛位来提高导电性,改善电化学特性。本文主要是通过高温固相法合成F-掺杂的尖晶石化合物Li4Ti5O12-xFx及对其电化学性能的影响。     

NASICON型Na~+交换材料的制备、表征与性能研究

采用高温固相两步法制备了两种Li1.4M0.4Ti1.6(PO4)3(M=Al、Cr)系列NASICON功能材料,对不同掺杂合成的样品进行了XRD和SEM表征,并分别对其Na+的交换吸附容量进行了测定。结果表明,对LiTi2(PO4)3掺入适量的Al3+和Cr3+后未改变其晶体结构,合成的吸附剂粒径分布在5~10μm;Li1.4M0.4Ti1.6(PO4)3(M=Al、Cr)对Na+有特效吸附作用,当pH=11.0时,Li1.4Al0.2Cr0.2Ti1.6(PO4)3的饱和交换吸附容量可达69.26mg/g。     

佼凝胶法合成Li4.4Al0.4Si0.6O4—xLi2O及电导性能

用溶胶－凝胶法制备了Li4.4Al0.4Si0.6O4-xLi2O(x=0.00-0.50）离子导体材料,并用DTA－TG、XRD、及交流阻抗等技术对样品进行了测试,结果发现：用溶胶－凝胶法可降低Li4.4Al0.4Si0.6O4的合成温度;随Li2O的掺入可增强基质材料的致密性并提高了其离子的导电性能。     

无机快离子导体材料的制备方法

系统地介绍快离子导体材料的制备方法及其进展，评论固相反应法、共沉淀法、溶胶－凝胶法、水热合成法、蒸发溶剂法等各咱方法的优点及存在问题和应用范围等。     

Photostriction of CH3NH3PbBr3 Perovskite Crystals

Organic–inorganic hybrid perovskite materials exhibit a variety of physical properties. Pronounced coupling between phonon, organic cations, and the inorganic framework suggest that these materials exhibit strong light–matter interactions. The photoinduced strain of CH₃NH₃PbBr₃ is investigated using high‐resolution and contactless in situ Raman spectroscopy. Under illumination, the material exhibits large blue shifts in its Raman spectra that indicate significant structural deformations (i.e., photostriction). From these shifts, the photostrictive coefficient of CH₃NH₃PbBr₃ is calculated as 2.08 × 10^?8 m² W^?1 at room temperature under visible light illumination. The significant photostriction of CH₃NH₃PbBr₃ is attributed to a combination of the photovoltaic effect and translational symmetry loss of the molecular configuration via strong translation–rotation coupling. Unlike CH₃NH₃PbI₃, it is noted that the photostriction of CH₃NH₃PbBr₃ is extremely stable, demonstrating no signs of optical decay for at least 30 d. These results suggest the potential of CH₃NH₃PbBr₃ for applications in next‐generation optical micro‐electromechanical devices.     

Constitution of the Ni3Cr-Ni3Al-Ni3W system

Isothermal sections of the Ni-Cr-Al-W system have been investigated at 75 at % Ni and temperatures of 1523 and 1273 K, by means of phase compositional analysis, X-ray diffraction and microscopical examination. The alloys studied lay in the range 2.5 to 10 at % Cr, 12.5 to 20 at% Al, 2.5 to 6.25 at % W, The phases formed were, and the bcc solid solution based on tungsten (designated ₂). The maximum extent of the region was found to be 3 at % each of chromium and tungsten. Preferential partitioning of tungsten to occurred. Study of an Ni-10Cr-12.5Al-2.5W alloy aged at 1273 and 1073 K, after quenching from 1573 K, showed that changes in and compositions and lattice parameters occur as a function of ageing time.     

(La2/3Ca1/3)(Mn(3-x)/3)Fex/3)O3体系磁电阻行为的研究

通过系统地测量（La_2/3Ca_1/3）（Mn_{（3-x）／3}Fe_x／3）O₃（x＝0、0.1、0．2、0．3的体系样品的电阻率-温度关系以及一定温度下磁电阻率与磁场的关系,发现随x的变化其磁电阻率峰和电阻率峰均发生位移,磁电阻率峰值增大,并伴生磁电阻率峰展宽效应．作者认为由于Fe的替代,引起体系中Mn³⁺／Mn⁴⁺比率及磁矩的变化,加之外场对磁有序结构的调制作用,从而影响了Mn³⁺－O^－Mn⁴⁺的双交换作用,最终导致磁电阻行为发生变化．     

PbZrO3-CdTiO3 solid solutions

The structural, nonlinear optical, and dielectric properties of (1-x)PbZrO₃ ·xtCdTiO₃ solid solutions were studied. The phase relations in the composition rangesx = 0–0.3 and 0.85-1.0 were established. The results suggest that the ferrielectric ordering in CdTiO₃ persists up to 730 K.     

3 Cr3 Mo3 VNb 在热冲孔中的应用研究

高合金钢热冲孔冲头寿命关系到模具与产品成本、生产效率、自动化设备的使用,因此,应注重冲头的选材、材料制备与冲头制造工艺。 用 3 Cr3Mo3 VNb 作为高合金钢热冲孔冲头,为提高模具寿命,在材料制备上,优化了成分,采用电渣重熔冶炼,减少杂质,毛坯锻造两次,用大锻造比锻造,冲头热处理用真空炉,三次回火,热处理硬度取 HRC42 ~ 46 ,冲头表面处理采用镀铬工艺,开展了热冲孔工艺试验。 结果表明,用3 Cr3Mo3 VNb 可使冲孔冲头寿命平均达到 800 件以上。     

Phase equilibria in the system LaMnO3 + δ-SrMnO3-LaFeO3-SrFeO3 − d

We have revealed the formation of a continuous series of orthorhombic LaMn_{1 ? y} Fe_yO₃ solid solutions (0<y<1); La_{1 ? x} Sr_xFeO₃ solid solutions in the composition range 0 < x ≤ 0.8, with an orthorhombic structure at 0 < x ≤ 0.6 and a cubic structure at 0.6 < x ≤ 0.8; and a tetragonal SrMn_{1 ? y} Fe_yO₃ phase in the range 0.6 ≤ y ≤ 1. The composition stability limits of the perovskite phase La_{1 ? x} Sr_xMn_{1 ? y} Fe_yO₃ have been determined, and the 1100°C isotherm of the La₂O₃-SrO-Mn₃O₄-Fe₂O₃ system in air has been constructed.     

Multicolor up-conversion emissions of Tm3+/Er3+/Yb3+ tri-doped YF3 phosphors

Tm3+/Er3+/Yb3+ tri-doped yttrium fluoride (YF3) phosphors were prepared by a facile hydrothermal method. X-ray topographic analysis found that the phosphors were crystallized products. Their sizes and morphologies were characterized by scanning electron microscopy (SEM, Hitachi S-4800), which indicated that most of the YF3 phosphors were hundreds of nanometers in size. Up-conversion (UC) spectra were recorded under 980-nm diode laser excitation at room temperature with a fluorescence spectrometer (Hitachi F-4500). Plenty of UC emissions of Tm3+ and Er3+ were observed from ultraviolet to red. For Tm3+ ions, a five-photon process (approximately 291 nm and approximately 347 nm), a four-photon process (approximately 362 nm and approximately 452 nm), and a three-photon process (approximately 475 nm) were identified in the UC spectra. The UC emissions from the Er3+ were: approximately 380 nm, approximately 408 nm, approximately 521 nm, approximately 537 nm, and approximately 652 nm. Therefore, cyan-white light can be observed by the naked eye at 980-nm excitation, even under low excitation power density. By comparing the UC spectra of the phosphors annealed at different temperatures, we found that the intensity of the UC luminescence increased as annealing temperature increased. Furthermore, the spectral dependencies on Tm3+ doped concentrations were studied. The energy transfer processes and fluorescence dynamics in the tri-doped system are currently being investigated.