Solid proton conducting electrolytes based on LaScO3

This study surveys the results obtained at the Institute of High Temperature Electrochemistry, Ural Branch, Russian Academy of Sciences on the physicochemical properties of proton-conducting materials based on LaScO₃ and analyzes the literature data.     

Solid polymer electrolytes based on Li+/ionic liquid for lithium secondary batteries

Journal of Solid State Electrochemistry - Ionic liquid (IL)-based solid polymer electrolytes (SPEs) were synthesized by solution cast technique using polymer polyethylene oxide (PEO), lithium...     

水热法制备Fe3+改性的SnO2纳米颗粒

采用水热法制备了Fe3+改性的SnO2纳米颗粒, 通过XRD、BET、TEM、FT-IR和紫外-可见漫反射光谱(DRS)对其结构和光学性质进行研究. 结果表明, 水热过程实现了氧化锡的直接晶化, 产物为金红石结构, Fe3+进入SnO2的晶格之中形成固溶体. 这种方法制备的Fe3+改性的SnO2纳米颗粒为单分散状态, 粒径分布均匀, 纯的SnO2未焙烧前平均粒径为6.0 nm, 随着Fe3+添加量的增大, 样品的粒径减小. BET显示纯的SnO2样品比表面积为206.1 m2•g−1, 随着Fe3+添加量增大, 产物的比表面积增大, 同时样品的紫外-可见吸收发生红移.     

Effect of Sb5+ codopant ions on the ultraviolet photocatalytic activity of Fe3+-modified anatase

1. Download : Download high-res image (81KB)
2. Download : Download full-size image

     

Solid polymer electrolytes based on crosslinkable polyoctahedral silsesquioxanes (POSS) for room temperature lithium polymer batteries

Solid polymer electrolytes (SPE), based on polyoctahedral silsesquioxanes (POSS) as a crosslinking agent, were prepared by radical polymerization. The ionic conductivity is greatly enhanced by introduction of crosslinkable POSS with multifunctional groups. The SPE prepared with 5 wt.% crosslinking agent shows an ionic conductivity of 5.3?×?10^?4 S cm^?1 at room temperature. The content of nonvolatile plasticizer, poly(ethylene glycol) dimethyl ether, in the SPE, could be raised to 95 wt.% without any leakage. The SPE is found to be electrochemically stable up to 5.3 V. Lithium polymer cell consisting of Li/SPE/LiCoO₂ exhibits 80% of initial discharge capacity even at the rate of 0.1 C at room temperature after 20 cycles, which is a substantial improvement for practical consideration of lithium polymer batteries at room temperature.     

Solid composite electrolytes based on zirconium hydrogen phosphate and polyaniline

The interaction in the zirconium hydrogen phosphate-polyaniline (PAN) system is studied using impedance and IR spectroscopy. Strong hydrogen bonds N-H...O and O-H...N are formed at the interface in this system. An appreciable increase in the ionic conductivity of composite materials based on zirconium hydrogen phosphate and PAN is discovered.     

Study on Gd3+ and Sm3+ co-doped ceria-based electrolytes

Doped ceria electrolytes of Ce_1-aGd_a-ySm_yO_2–0.5a, wherein a=0.15 or 0.2, and 0ya, were prepared with the citrate method, and characterized by inductively coupled plasma–atomic emission spectrometry, energy dispersive spectrometry, scanning electron microscopy, powder X-ray diffraction, and AC impedance spectroscopy. The effect of composition on the structure and conductivity was studied. All the samples were fluorite-type ceria-based solid solutions. For the singly doped samples, the optimal composition was Ce_0.85Gd_0.15O_1.925 for Gd³⁺-doped ceria (CGO), which showed higher ionic conductivity than the best Sm³⁺-doped ceria (CSO) at 773–973 K. For the co-doped samples, the ionic conductivities were higher than those of the singly doped ones in the temperature range 673–973 K when a=0.15, but only better in 673–773 K when a=0.2. For the samples of Ce_0.85Gd_0.15-ySm_yO_1.925, wherein 0.05y0.1, much higher ionic conductivity was observed than those of the singly doped ceria at 773K~973 K. Therefore, these co-doped samples would be better than CGO and CSO to be the electrolytes of intermediate-temperature solid oxide fuel cells.     

基于香豆素荧光团的高选择性Fe~(3+)荧光分子探针研究

设计合成了四种含有酰胺和酯基结构的香豆素荧光分子探针,其结构通过1H NMR、13C NMR和HRMS进行了表征,并对探针进行了常见金属离子识别性能的研究。发现该类探针对Fe3+产生荧光淬灭性响应,其中7-位带有二乙氨基的2-(7-二乙氨基香豆素-3-甲酰胺基)乙酸乙酯(C3)和3-(7-二乙氨基香豆素-3-甲酰胺基)乙酸丙酯(C4)对Fe3+的淬灭比例达到99.5%和99.6%,可作为识别Fe3+的探针。     

Nanosized Fe3O4-modified activated carbon for supercapacitor electrodes

Nanosized Fe₃O₄-modified activated carbon composites for supercapacitor electrodes have been investigated. Structural and morphological characterizations of activated materials are carried out using X-ray diffraction and scanning electron microscopy, respectively. The electrochemical performances of the composite electrodes are evaluated by cyclic voltammetry, chronopotentiometry and electrochemical impedance spectroscopy. The experimental results show that the specific capacitances of the 10 wt % Fe₃O₄-modified activated carbon composite electrode (154.3 F g^?1) is highly improved compared with that of Fe₃O₄ (78.5 F g^?1) and AC (79.2 F g^?1) at the current density of 5 mA cm^?2, respectively. The charge/discharge tests show that it could retain 79.6% of its initial capacitance over 1000 cycles, suggesting its potential application for the fabrication of high-quality supercapacitors.     

Solid and acid electrolytes for Al-air batteries based on xanthan-HCl hydrogels

Journal of Solid State Electrochemistry - This paper presents first investigations on solid and strongly acid electrolytes for Al-air batteries. These electrolytes are prepared starting from a...     

New solid polymer electrolytes based on polyester diacrylate for lithium power sources

New solid polymer electrolytes are developed for a lithium power source used at the temperatures up to 100°C. Polyester diacrylate (PEDA) based on oligohydroxyethylacrylate and its block copolymers with polyethylene glycol were offered for polymer matrix formation. The salt used was LiClO₄. The ionic conductivity of electrolytes was measured in the range of 20 to 100°C using the electrochemical impedance method. It is shown that the maximum conductivity in the whole temperature range is characteristic of the electrolyte based on the PEDA copolymer and polyethylene glycol condensation product (2.8 × 10^?6 S cm^?1 at 20°C, 1.8 × 10^?4 S cm^?1 at 95°C).     

Al3+-modified elastic properties of copper ferrite

Ultrasonic pulse echo-overlap technique at 300 K (9 MHz) has been employed to study the elastic properties of Al³⁺-substituted CuFe₂O₄ spinel ferrite system. The longitudinal and transverse wave velocities are used to compute elastic moduli and these are corrected to the zero porosity by employing different models. Contrary to expectation, the magnitude of elastic moduli is found to decrease by 75% with only 30% of Al³⁺-substitution for Fe³⁺ in the system. The lowering of elastic stiffness is mainly due to residual stress-induced spontaneous cracking and presence of oxygen vacant sites in the material. The lower value of lattice energy for polycrystalline specimens as compared to their single crystalline counterparts have been explained in the light of an increase degree of disorientation at the grain boundary with Al³⁺-substitution.     

Raman散射光谱定量分析铁电陶瓷掺杂诱导相转变现象

本文基于PZT基铁电体在准同型相界处各相的Raman散射模式,分析了Fe2O3掺杂对0.2PZN-0.8PZT铁电陶瓷Raman散射光谱的影响,建立了Raman散射模式与相结构之间的关系.结果表明,Raman散射分析可以作为陶瓷相结构定量分析的一种工具.     

浅谈检验Fe~(2+)与Fe~(3+)的误区

空白试验证明,用浓度大于1mol/L的盐酸溶液做Fe~(3+)的提取液,或用过浓盐酸溶液酸化试液,盐酸中的Fe~(3+)都会给检验试液中的Fe~(3+)带来干扰;检验食品中的铁元素时,若铁是以Fe~(2+)形式存在,如果加入硝酸将其氧化为Fe~(3+),硝酸中Fe~(3+)会对检验试液中的Fe~(3+)带来干扰。     

Sol-gel electrolytes in lithium batteries

This paper presents the results of the thermodynamic calculations of material compatibility along with the results of the experimental studies using lithium aluminosilicate gel electrolyte in lithium batteries. Initially, there were problems with gel monoliths and porous cathodes in the Li solid electrolyte batteries. Better results were obtained through the direct application of thin films of the lithium aluminosilicate gels to the surfaces of dense, sintered oxide cathodes. It was important to maintain extremely low moisture and oxygen levels in the dry glove box during the assembly and testing of the battery, especially when it came to achieving good contact between the sol-gel electrolyte and the lithium metal. Suggestions are given about procedures for further development of the sol-gel electrolyte batteries.     

New lithium ion conducting polymer electrolytes based on polysiloxane grafted with Si-tripodand centers

New kind of polymer host for lithium cations has been synthesized by catalyzed hydrosilylation reaction involving hydrogen atoms of a polysiloxane and double bonds of vinyl tris-2-methoxyethoxy silane. The obtained macromolecule can be regarded as siloxane backbone grafted with silicon tripodand elements with very short polyether chains. A family of Li ion conducting polymer electrolyte membranes have been prepared by dissolving LiPF₆ in thus obtained polymer matrix. Exceptionally high room temperature specific conductivities, exceeding 10⁻³ S/cm at 25 °C, have been measured for the studied polymer electrolytes. It is proposed that polyether chains tend to self-assembly in the presence of Li cations and this highly organized arrangement of Li coordination sites creates pathways of high lithium conductivity along the polysiloxane backbones. In addition to that, strong shielding of Li-cations suppresses the formation of ion pairs, thus increasing the charge carrier concentration. The electrolytes can be easily formed into dimensionally stable, flexible membranes.     

Self-diffusion of lithium cations and ionic conductivity in polymer electrolytes based on polyesterdiacrylate

The processes of ionic conductivity are studied in a polymer gel electrolyte synthesized based on polyesterdiacrylate and a low-molecular solvent ethylene carbonate. The self-diffusion coefficients of solvent molecules and Li⁺ cations are measured by the NMR with the pulsed magnetic field gradient. The Li⁺ self-diffusion coefficients increase with the increase in the solvent content and are independent of the diffusion time in the interval from 10 to 1600 ms. The latter values imply the absence of limitations for the translational mobility of lithium ions in the spatial range from 10⁻⁷ to 10⁻⁵ m. Based on the Nernst-Einstein equation, the ionic conductivities are calculated and compared with the experimental conductivities measured by the impedance method. These values coincide for high contents of solvent; for low ethylene carbonate concentrations, the calculated conductivities much exceed the experimental values.     

Synthesis and electrochemistry of polymer based electrolytes for lithium batteries

An overview is presented on the development of improved polymer based electrolytes during the past years. The emphasis lies on new approaches regarding chemical concepts that achieve a higher total conductivity and lithium transference number as well as an increased electrochemical, mechanical and thermal stability. With respect to the polymer chemistry, the focus is laid on siloxane and phosphazene derived systems. Topics are the chemical modification of the polymeric, cyclic and low molecular derivates of these systems, the formation of stable membranes from these by suitable cross-linking strategies and an extensive electrochemical characterization in corresponding lithium cells. Recent trends towards composite and hybrid materials are illustrated with examples and newly developed hybrid electrolytes. A particular chance for improvements comes from the design and use of stable small molecular additives in combination with optimized and electrochemically stable polymer networks. Special compounds are introduced which may act themselves as novel solvents with increased electrochemical stabilities. The relevance of chosen lithium salts for polymer electrolytes is discussed, too, and a new family of pyrazolide anions is introduced. In all cases, the electrochemical performance has been characterized by standard experimental techniques.     

All solid polymer electrolytes based on polar side group rotation for rechargeable lithium batteries

A novel polymer matrix with a polar carbonyl group was designed and used to prepare an all‐solid polymer electrolyte in lithium rechargeable batteries. The ionic conductivity of this type of polymer electrolyte was examined. The relationship between the lithium salt concentration and ionic conductivity was investigated by Fourier transform infrared (FTIR) spectroscopy. The carbonyl groups in the polymer matrix effectively interacted with the lithium salt, which improved the ionic conductivity at a large range of temperatures. The ionic conductivity of this type of polymer electrolyte was approximately 10^?4 S cm^?1 at room temperature. The stability of the interface between electrode and electrolyte was evaluated by measuring the alternating current (AC) impedance. Copyright © 2009 John Wiley & Sons, Ltd.     

Review on gel polymer electrolytes for lithium batteries

This paper reviews the state-of-art of polymer electrolytes in view of their electrochemical and physical properties for the applications in lithium batteries. This review mainly encompasses on five polymer hosts namely poly(ethylene oxide) (PEO), poly(acrylonitrile) (PAN), poly(methyl methacrylate) (PMMA), poly(vinylidene fluoride) (PVdF) and poly(vinylidene fluoride-hexafluoro propylene) (PVdF-HFP) as electrolytes. Also the ionic conductivity, morphology, porosity and cycling behavior of PVdF-HFP membranes prepared by phase inversion technique with different non-solvents have been presented. The cycling behavior of LiMn₂O₄/polymer electrolyte (PE)/Li cells is also described.