三维钴基MOF[KCo7(OH)3(ip)6(H2O)4]·12H2O作为超级电容器的高容量电极材料

为了开发较高能量密度的超级电容器,我们通过简单的溶剂热反应合成了一种三维的钴基金属有机框架(MOF)化合物([KCo7(OH)3(ip)6(H2O)4]·12H2O,Co?ip;ip=间苯二甲酸根),并考察了其作为超级电容器电极材料的性能。Co?ip电极显示出高比电容、良好的循环稳定性和优良的倍率性能。在1 mol·L^-1 KOH溶液中,电流密度为1 A·g^-1时,其最大比电容为1660 F·g^-1。在电流密度为2 A·g^-1条件下,循环3000次后,其比电容的保持率为82.7%。优异的超级电容性能可归因于Co?ip具有纳米尺寸颗粒和三维的多孔结构。     

Core‐Shell Structured Layered Lanthanide‐Organic Complexes with Stilbazolium‐type Dye Encapsulation for Multifunctional Performances

Host‐guest encapsulation of functional organic dye into a porous metal‐organic framework can give rise to the development of new functional materials. In this work, by intercalating the stilbazolium‐type dye (DEAST)I (4′‐diethylamino‐N‐methyl stilbazolium) into four lanthanide layered metal‐organic complexes (Ln‐LMOCs), i. e. {[Ln(BTB)(H₂O)₂]?3(DMF)?2(H₂O)}_n (Ln=La (1), Nd (2), Sm (3), Er (4)), four responsive (DEAST)I@Ln‐LMOC composites have been prepared, serving as multifunctional performance platform. The core–shell structures of (DEAST)I@Ln‐LMOC composites have been fully characterized by IR, UV/Vis, PXRD, SEM, TEM, TGA and ESR. Significantly, after intercalation of dyes, the (DEAST)I@Ln‐LMOC composites exhibit enhanced luminescent sensing properties in detecting Fe³⁺ with much higher water stabilities. The luminescent sensing behavior stems from the fluorescence resonance energy transfer (FRET) from the π‐electron‐rich BTB ligands to the Fe³⁺, and their higher water stabilities are induced by electrostatic interactions and lower porosity. Specially, the characteristic emissions of Sm³⁺ will not be affected after the encapsulation guest dyes, which provide a theoretical guide for the modulation of luminescence devices. Finally, better ion conductivities and diminished photocurrents can be achieved after the embedding of the functional organic dye. In all, the formation of (DEAST)I@Ln‐LMOC composites with core–shell structures can be utilized as a multifunctional platform with good stability.     

Significantly improved photovoltaic performances of the dithiophene‐benzothiadiazole‐alt‐fluorene copolymers by incorporating carbazole units in fluorene moiety

To exploit an effective way to improve polymeric photovoltaic performance, a series of dithiophene‐benzothiadiazole‐alt‐fluorene copolymers containing carbazole groups at C‐9 positions of the alternating fluorene units (PFO‐FCz‐DBT) were synthesized and characterized. The effect of the carbazole groups on the optophysical, electrochemical, and photovoltaic properties of these copolymers was investigated. By comparison, this type of copolymers with carbazole units exhibited significantly improved photovoltaic properties than poly(2,7‐(9,9‐dioctyl‐fluorene)‐alt‐5,5‐(4′,7′‐di‐2‐thienyl‐2′,1′,3′‐benzothiadiazole) (PFO‐DBT) in the bulk heterojunction solar cells. A maximum power‐conversion efficiency (PCE) of 2.41% and a highest short‐circuit current density (J_sc) of 9.68 mA cm^?2 were obtained for the PFO‐FCz‐DBT30, which are about two times higher than the corresponding levels for the PFO‐DBT30. This work demonstrated that introducing a hole‐transporting carbazole unit into copolymer is a simple and effective method to improve the J_sc and PCE. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

稀土镧在腈纶纤维化学镀银中的应用及其电化学性能

采用化学镀法(镀液中加入适量的稀土镧)在硅烷偶联剂改性后的腈纶纤维表面沉积金属银,由粒径分析、X射线衍射、扫描电子显微镜、阴极极化曲线以及循环伏安曲线等方法对其进行表征,研究了硝酸镧对化学镀银沉积速度、镀层质量和电化学性能的影响。结果表明,镀银液中加入适宜的硝酸镧,银的沉积速率和腈纶纤维表面银镀层的表面质量均有不同程度的提高。电化学测试表明,镀银液中增大硝酸镧的浓度(0～0.01 g/L),阴极极化曲线极化度增大,氧化还原峰的电流上升,电沉积的速度加快。     

Tribological behaviors of a novel trilayer nanofilm: the influence of outer chain length and interlayer thickness

Polydopamine (coded as PDA) is reported to be very adhesive and reactive due to the attached functional groups, such as amine and hydroxyl groups. In this work, taking advantage of the condensation between Si–OH of the hydroxylated alkyltrichlorosilane (ATS) and C–OH on PDA surface, ATS molecules with different chain carbon number of 10, 14 and 18 were grafted onto the 3‐aminopropyl triethoxysilane (APTES)‐PDA dual‐layer film, which was composed of PDA outerlayer and APTES underlayer, on Si substrate. Thus, hydrophobic trilayer films coded as APTES‐PDA‐ATS were prepared successfully. In order to reveal the dependence of the tribological behaviors upon the microstructures of the film, tribological experiments were conducted on an atomic force microscope and a ball‐on‐plate tribometer. Experimental results showed that the (micro‐) friction reducing (characterized by a parameter of relative friction coefficient or friction coefficient, RFC or FC) and macro‐wear resisting (characterized by anti‐wear life) behaviors were related with the chain length of outerlayer and the PDA thickness. Specifically, on one hand, as the chain length increases, RFC/FC decreased and macro anti‐wear life lengthened; on the other hand, as PDA gets thicker, RFC increased and the anti‐wear life enhanced. Copyright © 2013 John Wiley & Sons, Ltd.     

铌酸锂晶体性能的组成依赖性(英文)

总结了铌酸锂晶体的各项性能指标,显示了其对晶体实际组成的强烈依赖性.利用化学键模型定量地解释了这种依赖性产生的根源,从而说明了制约该晶体性能提高的关键因素是晶体结构中的缺陷控制.     

PREPARATION AND ELECTROCHEMICAL CHARACTERISTICS OF POLYMER ELECTROLYTE MEMBRANES BASED ON SAN/PVDF-HFP BLENDS

A copolymer of poly(acrylonitrile-co-styrene) (SAN) was synthesized via an emulsion polymerization method. Novel polymer electrolyte membranes cast from the blends of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), SAN and fumed silica (SiO2) are microporous and can be used in polymer lithium-ion batteries. The membrane shows excellent characteristics such as high ionic conductivity and good mechanical strength when the mass ratio between SAN and PVDF-HFP and SiO2 is 3.5/31.5/5. The ionic conductivity of the membrane soaked in a liquid electrolyte of 1 mol/L LiPF6/EC/DMC/DEC is 4.9×10-3 S cm-1 at 25℃. The membrane is electrochemical stable up to 5.5 V versus Li /Li in the liquid electrolyte. The influences of SiO2 content on the porosity and mechanical strength of the membranes were studied. Polymer lithium-ion batteries based on the membranes were assembled and their performances were also studied.     

表面活性剂在离子选择电极分析中的增敏作用

本文以涂丝Ag-Ag2S电极为指示电极,饱和甘汞电极和自制锑电极为参比电极,分别试验了加入阳离子、阴离子和非离子表面活性剂对电极灵敏度的影响。结果表明,加入非离子表面活性剂对电极响应无明显影响,但阴离子和阳离子表面活性剂可使电极灵敏度有较大提高;其中,十六烷基三甲基溴化铵(CTMAB)和十二烷基苯磺酸钠(SDBS)、十二烷基硫酸钠(SDS)对电极的增敏效果显著,可使电极响应线性范围下限扩大一个数量级左右,且电极响应时间缩短,稳定性提高。     

Lu2O3对球形Ni(OH)2高温充放电性能的影响

为了改善镍电极的高温充电效率，采用机械混合的方式将球形Ni(OH)2与不同比例的Lu2O3混合后制成粘结式镍正极。充放电测试、循环伏安和XRD等实验结果表明，掺杂Lu2O3后镍电极的析氧过电位明显提高，高温充电效率得到了很大改善，在充电后的电极中β-NiOOH生成；而且Lu2O3的掺杂比例对镍电极的高温性能在不同的充放电倍率下有不同程度的影响，3．5％是最好的掺杂比例，掺杂对高温小电流充电效率的改善作用要大于高温大电流充电。     

Enhanced Electrochemical Performances of LiFePO4/C via V and F Co-doping for Lithium-Ion Batteries

Based on the method of in situ polymerization synthesis combined with two-step sinter-ing process, LiFe_1-xV_x(PO₄)_(3-y)/₃F_y/C was prepared. The e ects of V and F co-doping on the structure, morphology, and electrochemical performances of LiFePO₄/C were in-vestigated by X-ray di raction, Fourier transform infrared spectra, scanning electron mi-croscope, charge/discharge tests, and electrochemical impedance spectroscopy, respectively. The results indicated that the V and F co-doping did not destroy the olivine structure of LiFePO₄/C, but it can stabilize the crystal structure, decrease charge transfer resistance, enhance Li ion di usion velocity, further improve its cycling and high-rate capabilities of LiFePO₄/C.