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The stability, elastic properties and conductive properties of Cu-doped SnO2, S-doped SnO2 and Cu, S-codoped SnO 2were studied by using the first-principles calculation method based on the density functional theory. The corresponding doped SnO2 powders were prepared by sol–gel method, while AgSnO2–Cu and AgSnO2–Cu–S contacts were obtained by powder metallurgy method for experimental verification. No diffraction peaks were associated with Cu and S in the XRD patterns of the doped SnO2 powders, indicating that the doped SnO2 retained the tetragonal crystal structure. The doping formation energy of Cu, S co-doped system was found to be lower than that of Cu single doping system and S single doping system. The bulk modulus, shear modulus and Young's modulus of the co-doped system became lower, the ability to resist compression deformation and shear deformation was also weakened, while its toughness was greatly improved. The hardness of the AgSnO2–Cu–S contact was 103.55 HV, which is less than the hardness of the AgSnO2–Cu contact (112.86 HV). The calculations indicated that Cu, S co-doping could narrow the band gap, reduce the hole effective mass and the acceptor ionization energy, improve the hole mobility, and enhance the conductivity of the material. The electrical contact simulation experiments showed that the conductive properties, arc corrosion resistance and welding resistance of AgSnO2–Cu–S contact were better than those of the AgSnO2–Cu contact. The conductivity of AgSnO2–Cu–S contact was 29.948 mS · m–1, the contact resistance was 1.109 Ωm ; the average arc duration and average arc energy were 1.480 ms and 171.65 mJ, respectively.

Carrier recombination and charge loss at the interfaces of perovskite layers have a significant influence on high-performance planar perovskite solar cells (PSCs). We employed two-dimensional graphitic carbon nitride (g-C3N4), which is a heat-resistant n-type semiconductor, to modify the electron-transport layer/perovskite and perovskite/hole-transport layer interfaces, respectively. g-C3N4 could passivate the surface trap states of the methylammonium lead iodide light absorber through the formation of a Lewis adduct between N and the under-coordinated Pb, and it could also remarkably reduce the grain boundaries between perovskite crystal particles. A maximum power conversion efficiency (PCE) of 19.67% (Voc = 1.14 V, Jsc = 21.45 mA cm−2, FF = 0.807) could be obtained from planar PSCs with long-term stability using dual-positioned g-C3N4. Therefore, we consider that ultrathin semiconductor films with a Lewis base nature are suitable as dual-functional transport materials for devices. This work provides new guidance for dual-interfacial modification to improve the PCE and stability of devices.

Hydrogen energy, as an ideal renewable resource and green energy replacement, has attracted growing attention. However, constructing highly active and stable catalysts for hydrogen evolution from Formic acid (FA) is still a challenging issue for development of renewable hydrogen energy. Herein, we develop a facile defect engineering strategy to construct N-deficient ordered mesoporous graphitic carbon nitride coupled with AgPd nanoparticles (denoted as AgPd/N-ompg-C3N4). Impressively, the as-prepared Ag0.1Pd0.9/N-ompg-C3N4 catalyst exhibits remarkable activity with the Turnover frequency (TOF) value of 1588.2 h−1 and robust stability with only a slight decrease in activity after ten cycles. Such markedly enhanced catalytic performance of Ag0.1Pd0.9/N-ompg-C3N4 is mainly attributed to the unique structure of N-ompg-C3N4 with higher surface area and abundant surface defects, the strong metal − support interaction between AgPd and N-ompg-C3N4, and charge transfer from Pd to Ag. This study provides a novel and efficient strategy for designing efficient catalysts to drive the hydrogen evolution from FA.

Hydrous hydrazine (N2H4∙H2O) is a candidate for a hydrogen carrier for storage and transportation due to low material cost, high hydrogen content of 8.0%, and liquid stability at room temperature. Pt and Pt nanoalloy catalysts have been welcomed by researchers for the dehydrogenation of hydrous hydrazine recently. Therefore, in this review, we give a summary of Pt nanoalloy catalysts for the dehydrogenation of hydrous hydrazine and briefly introduce the decomposition mechanism of hydrous hydrazine to prove the design principle of the catalyst. The chemical characteristics of hydrous hydrazine and the mechanism of dehydrogenation reaction are briefly introduced. The catalytic activity of hydrous hydrazine on different supports and the factors affecting the selectivity of hydrogen catalyzed by Ni-Pt are analyzed. It is expected to provide a new way for the development of high-activity catalysts for the dehydrogenation of hydrous hydrazine to produce hydrogen.

Hydrogen energy is considered to be a desired energy storage carrier because of its high-energy density, extensive sources, and is environmentally friendly. The development of hydrogen storage material, especially liquid organic hydrogen carrier (LOHC), has drawn intensive attention to address the problem of hydrogen utilization. Hydrogen carrier is a material that can reversibly absorb and release hydrogen using catalysts at elevated temperature, in which LOHC mainly relies on the covalent bonding of hydrogen during storage to facilitate long-distance transportation and treatment. In this review, the chemical properties and state-of-the-art of LOHCs were investigated and discussed. It reviews the latest research progress with regard to liquid organic hydrogen storage materials, namely N-ethylcarbazole, and the recent progress in the preparation of efficient catalysts for N-ethylcarbazole dehydrogenation by using metal multiphase catalysts supported by carbon–nitrogen materials is expounded. Several approaches have been considered to obtain efficient catalysts such as increasing the surface area of the support, optimizing particle size, and enhancing the porous structure of the support. This review provides a new direction for the research of hydrogen storage materials and considerations for follow-up research.

Bi-bearing Al-Ga-In-Sn quinary alloys were prepared by a high-temperature melting technique. The alloys primarily consist of Al(Ga) matrix and Ga, In, Sn, Bi (GISB) grain boundary phase, mainly in the form of Ga-InSn4-InBi. The microstructure of GISB particles was obviously equiaxed with the increasing Bi dosage. Al-water reaction was tested at 40 °C. Owing to the Bi-doping, the hydrogen generation yields of alloys with InSn4 intermetallic compound are obviously improved and hydrogen release rates gradually tend to be stable, which show great potential in applications. At the dosage of 2.53 wt% Bi, the hydrogen generation performance of alloys was more prominent in Al-water reaction, including a theoretical hydrogen generation yield and hydrogen released extremum rate to ∼0.076 L/min·g Al alloy. Furthermore, the Al-water reaction mechanism of Bi-bearing Al-rich low-In quinary alloys has been put forward.

Cu-containing Al-Ga-InSn4 quinary alloys were prepared by a simple smelting method under a high-purity nitrogen atmosphere, and the alloys were cast at room temperature. The microstructures were investigated using X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy-dispersive X-ray (EDX) spectroscopy analysis. In addition to the InSn4 intermetallic compounds, elemental Cu was found in the alloys. As the Cu content increased, more holes and cracks were formed, and the Al(Ga) solid solution was pulverized. The melting points of Al compounds with the other elements were determined by differential scanning calorimetry (DSC). The alloy and water reactions were investigated at a water temperature of 40 °C. The Cu addition not only increased the hydrogen yield of the Al-Ga-InSn4 alloys but also stabilized the hydrogen generation from the Al-water reaction, which indicated that the Al-Ga-InSn4-Cu alloys are more suitable as fuel hydrogen sources for proton exchange membrane fuel cells. Based on the DSC and SEM with EDX studies, we propose the reasons for the changes in the Al-water reaction with the Cu addition.

Ni-rich cathodes used in lithium-ion batteries can provide a desirable increase in energy density due to their high specific capacity, such as NMC622 (LiNi0.6Co0.2Mn0.2O2) and NMC811 (LiNi0.8Co0.1Mn0.1O2). However, the higher capacity of Ni-rich cathodes comes with a downside: faster capacity fade and lower cycling stability. The source of capacity fade for these cathodes has been attributed to multiple degradation mechanisms including particle cracking[1], irreversible structural changes[2], and side reactions that catalyze electrolyte decomposition[3]. Previous studies have shown evidence that electrolyte additives that influence the cathode surface can inhibit cycling-induced degradation with high-nickel cathodes[4,5]. In this study, we investigate the cycling stability of multi-layer pouch cells with NMC622 or NMC811 cathodes and graphite anodes, and the effects of different additives on cycling performance and impedance. Our study shows that in batteries with Ni-rich cathodes, organosilicon additives significantly improve cycling stability, as well as reduce gas generation during cycling. We use XPS to study the electrode surface compositions after different stages of cycling, and specific surface features are identified that correlate to performance and impedance over the course of cycling. NMR is used to monitor the consumption of additives from the liquid electrolyte. Through depth profiling and XPS signal attenuation, the surface layer thicknesses on the anodes and cathodes are estimated, and compared across different cycling protocols and different additives. It is proven that organosilicon additives alter the cathode and anode surface compositions, and the effect of changing the additive concentration on cycling stability and the electrode surfaces is also demonstrated. Varying structural features on the organosilicon additives, such as the degree of fluorination and type of functional group, are shown to impact the electrode interaction, impedance, and cycling stability. The impact of additives on reducing gas generation and affecting the gas composition is also quantified by the Archimedes method and gas chromatography. Overall, through this study we aim to provide enhanced understanding of the role of surface chemistry as an agent and an indicator of battery performance, and the effects of additives on surface chemistry and cycling stability. S. Oswald, D. Pritzl, M. Wetjen, H. A. Gasteiger, J. Electrochem. Soc., 167 (2020) 100511. C. Xu, K. Märker, J. Lee, A. Mahadevegowda, P. J. Reeves, S. J. Day, M. F. Groh, S. Emge, C. Ducati, B. L. Mehdi, C. C. Tang, C. P. Grey, Nat. Mater. (2020). A. T. S. Freiberg, M. K. Roos, J. Wandt, R. de Vivie-Riedle, H. A. Gasteiger, J. Phys. Chem. A, 122 (2018) 8828. T. Yim, K. S. Kang, J. Mun, S. H. Lim, S-G. Woo, K. J. Kim, M-S. Park, W. Cho, J. H. Song, Y-K. Han, J-S. Yu, Y-J. Kim, J. Power Sources, 302 (2016) 431. K. Kim, Y. Kim, S. Park, H. J. Yang, S. J. Park, K. Shin, J-J. Woo, S. Kim, S. Y. Hong, N-S. Choi, J. Power Sources, 396 (2018) 276.

SnO2 has attracted extensive attention in planar perovskite solar cells (PSCs) owing to its outstanding photoelectric properties and low temperature preparation. However, pinholes are easy to appear in the annealing process of SnO2 films, which limits its application in planar PSCs. Here lists a simple and low-cost method: Urea-complexed tin oxide in deionized water can effectively control the concentration of SnO2. This process is conducive to forming a compact surface morphology. Meanwhile, the work explored the effect of the properties of PSCs with different thicknesses of SnO2 layers. The system analysis showed that PSCs based on 60 nm SnO2 layer and the methamphetamine lead iodide (MAPbI3) light absorber yielded the highest power conversion efficiency (PCE) over 18%, a fill factor (FF) of 0.793, and good stability. Therefore, we believe our study provides an effective way for preparing electron transport layers.

The battery industry is constantly seeking to improve battery capacity, lifetime, and safety. Electrolytes are a key development focus in achieving these goals, as traditional carbonate-based electrolytes cause capacity fade and gassing through degradation processes, as well as representing a safety risk due to flammability. The release of gasses through electrolyte decomposition is a problem of prominent concern in the battery industry, due to the negative impact of gassing on cell safety and performance. Studies on battery gassing have been reported for a wide range of battery systems,1-3 but the mechanisms and conditions of gas release are complex and not fully understood. Gaining a greater understanding of gassing mechanisms, and the specific electrolyte components that cause them, will allow for precise design of battery electrolyte formulations that optimize performance and minimize gassing. In addition to understanding traditional electrolyte blends, the investigation of new electrolytes and additives is essential in developing low-gassing batteries. Organosilicon (OS) materials have been developed by Silatronix® as critical high stability additions to conventional carbonate electrolytes to enable next-generation Li-ion batteries. This novel organosilicon chemistry involves the merging of a silane with a Li+ coordinating functionality. For example, the OS3® solvent family contains a nitrile functionality. The adoption of new Li-ion battery electrolyte materials is driven by the desire to deploy higher energy density batteries capable of performing under broader operating conditions of temperature and voltage, and the design of OS solvents results in low molecular-weight molecules that have demonstrated superior thermal and electrochemical stability,4,5 as well as good safety properties with a high flash point and low vapor pressure. Silatronix® has conducted commercially relevant performance testing and fundamental mechanistic studies to investigate gassing phenomena in advanced Li-ion chemistries under both cycling and storage test conditions. In these studies, commercially relevant electrolytes were evaluated as well as electrolytes designed to specifically isolate the effect of selected electrolyte components, including OS3® and other industry-relevant solvents. The dependence of gassing on storage and voltage conditions was investigated, and connections between gas analysis and the electrode surface chemistry are also reported. Gas component analysis was performed with a calibrated dual-column GC-TCD, a similar analytical system to that utilized in previous studies,6 which provides excellent resolution and quantification of every gaseous product. Key experimental results show that all OS3® concentrations reduce gas generation after 60°C storage and higher OS3® content provides greater benefit. Overall, we show that organosilicon additives substantially reduce gassing from carbonate-based electrolytes while maintaining good cell performance. Zhang, S.S., Insight into the Gassing Problem of Li-ion Battery. Frontiers in Energy Research 2014, 2, 59. Self, J.; Aiken, C.P.; Petibon, R.; Dahn, J.R., Survey of Gas Expansion in Li-Ion NMC Pouch Cells. Journal of the Electrochemical Society 2015, 162, A796-A802. Jung, R.; Metzger, M.; Maglia, F.; Stinner, C., Chemical vs Electrochemical Electrolyte Oxidation on NMC111, NMC622, LNMO, and Conductive Carbon. The Journal of Physical Chemistry Letters 2017, 8, 4820-4825. Guillot, S.L.; Peña-Hueso, A.; Usrey, M.; Hamers, R.J., Thermal and Hydrolytic Decomposition Mechanisms of Organosilicon Electrolytes with Enhanced Thermal Stability for Lithium-Ion batteries. Journal of the Electrochemical Society 2018, 164, A1907-A1917. Chen, X.; Usrey, M.; Peña-Hueso, A.; West, R.; Hamers, R.J., Thermal and Electrochemical Stability of Organosilicon Electrolytes for Lithium-Ion Batteries. Journal of Power Sources 2013, 241, 311-319. Xiong, D.J.; Ellis, L.D.; Petibon, R.; Hynes, T.; Liu, Q.Q.; Dahn, J.R., Studies of Gas Generation, Gas Consumption and Impedance Growth in Li-Ion Cells with Carbonate or Fluorinated Electrolytes Using the Pouch Bag Method. Journal of the Electrochemical Society 2017, 164, A340-A347.

The surface acoustic wave (SAW) characteristics of Y-cut X propagating Pb(In 1/2 Nb 1/2 )O 3 -Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 (YX-PIMNT) single crystals on a diamond substrate have been theoretically calculated. The simulated results show that the phase velocity of the shear horizontal (SH) SAW may be greatly enhanced from the 1350 m/s to 3350 m/s by reducing the thickness of the PIMNT from 0.5 λ to 0.05 λ , with a corresponding decrease in the electromechanical coupling factor ( K 2 ) from 73.6% to 19.6%. The dispersion curves of phase velocity and K 2 as a function of PIMNT thickness are given for the proposed layered structure. Besides the SH SAW, there are also higher order modes that would cause unwanted responses in the pass-band of wideband SAW filters. These were suppressed by properly controlling structural parameters including top electrode thickness, thickness and Euler angle (θ) of PIMNT substrate. The calculated results demonstrate the effectiveness of this approach to enlarge the phase velocity of the SH SAW without dramatically sacrificing its K 2 , which makes relaxor based ferroelectric single crystals promising for realizing ultra-wideband SAW devices working in ~ GHz range.

A novel series of lithium alkyl trimethyl borates and lithium aryl trimethyl borates have been prepared and investigated as cathode film forming additives. The borates are prepared via the reaction of lithium alkoxides or lithium phenoxides with trimethyl borate. Incorporation of 0.5–2.0% (wt) of the lithium borates to a baseline electrolyte (1.0 M LiPF6 in 3 : 7 (EC/EMC)) results in improved capacity retention and efficiency of high voltage graphite/LiNi0.5Mn1.5O4 cells especially upon cycling at elevated temperature (55 °C). The improved performance results from the sacrificial oxidation of the lithium borate on the cathode surface to generate a cathode passivation film. The lithium borates can be readily structurally modified to act as a functional group delivery agent to modify the cathode surface. Ex situ surface analysis of the electrodes after cycling confirms that the lithium borates modify the cathode surface and generate a borate rich surface film which inhibits electrolyte oxidation and Mn dissolution.

Two dimensional graphitic carbon nitride nanosheets (2D CNNs), as novel types of emerging materials, have aroused considerable research enthusiasm in recent years. Herein, we describe for the first time a new application of 2D CNNs as an ideal scaffold for synthesizing AgPd/2D CNNs through a facile one-step reduction method and further utilized it as catalysts toward photocatalytic hydrogen generation from FA under visible light (λ > 400 nm). Benefiting from plasmonic and Mott-Schottky, alloying effects, as well as the unique 2D nanosheets structure with a high surface area, the resultant Ag0.1Pd0.9/2D CNNs affords superior performance under visible light, including 100% H2 selectivity, 100% conversion, cycle performance, hydrogen evolution rate of 231.6 mmol h−1and the corresponding TOF value of 2936.8 h−1, which is 1.87 times and 3.5-fold higher than that of Ag0.1Pd0.9/2D CNNs under no light (1573.5 h−1) and that of Ag0.1Pd0.9/CN (837.2 h−1) under visible light, respectively, even better than most of the noble metal heterogeneous catalysts. This study not only throws light on modulating the structure of g-C3N4 to enhance the photocatalytic activity toward hydrogen evolution reaction but also offers a versatile method for developing high-performance photocatalyst for hydrogen economy and other applications.

Lithium ion batteries are complex systems with multiple components that can be optimized to obtain desired performance capability. These components include electrolyte salts, solvents, and additives, as well as electrode active materials and coatings. Rational optimization of battery components requires an understanding of the fundamental science driving the observed performance. Silatronix® has developed a suite of analytical tools and methods using a combination of full format batteries, lab R&D cells, and model systems to construct a complete understanding of the battery from the cell level performance to the fundamental chemistry. This process includes the recovery and analysis of all parts of a full format pouch cell, including liquid electrolyte, generated gas, and electrode surface layers (Fig. 1). Using this process, Silatronix® has evaluated several battery components, including organosilicon solvents for Li-ion electrolytes, to acquire a comprehensive picture of how these components provide observed performance benefits. For example, OS3®, a novel organosilicon chemistry that merges a silane with a Li+ coordinating nitrile functionality, has provided multiple performance benefits in various advanced Li-ion chemistries. Key experimental results include improved high temperature cycling stability in full format graphite/NMC622 pouch cells with 1%, 2%, or 3% OS3® (Fig. 2a), and using a model system of electrolyte in NMR tubes, we show that enhanced thermal stability of the bulk electrolyte results from HF scavenging and LiPF6 salt stabilization when 2-16% OS3® is present (Fig. 2b). Reduction of gas generation during high temperature testing in pouch cells with a commercial Si-based anode is also shown with 2% OS3® (Fig. 2c), and gas product identification and quantification is determined by GC-TCD for mechanistic analyses. In addition, OS materials change the reactivity of other electrolyte components, particularly at the electrolyte/electrode interfaces that govern critical performance attributes in Li-ion cells such as gas generation and interfacial impedance. These key performance benefits serve to enable several next generation battery chemistries, including a strong synergy with Si-based anodes. Figure 1

Al2O3-added Al-Ga-In-Sn alloys were prepared using a smelting and casting method. As the Al2O3 is added, the Al grain will be refined. With the refinement of the Al grain, the size of grain boundary particle decreases slightly, and under these circumstances, the reaction rate of Al-water is improved. Al-2.5Ga-5.58In-1.92Sn-1.0Al2O3 alloys exhibit maximum rate of hydrogen production. Alloys with stable hydrogen production rates in all Al2O3-added formulations have also been investigated, and this demonstrates potential applications in proton exchange membrane fuel cells. The reasons for the changes in the microstructure and Al-water reaction with the Al2O3 addition was supposed.

Lithium tetramethyl borate (LTMB, LiB(OCH3)4) has been prepared and investigated as a novel cathode film forming additive to improve the performance of LiNi0.5Mn1.5O4 cathodes cycled to high potential (4.25-4.8 V). Addition of LTMB to 1.2 M LiPF6 in EC/EMC (3/7, v/v) improves the capacity retention of graphite/LiNi0.5Mn1.5O4 cells cycled at 55◦C. The added LTMB is sacrificially oxidized on the surface of the cathode during the first charging cycle. Ex-situ surface analysis of the LiNi0.5Mn1.5O4 by X-ray photoelectron spectroscopy (XPS) reveals the presence of a borate based passivating layer which appears to inhibit electrolyte oxidation on the cathode surface. © The Author(s) 2015. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives 4.0 License (CC BY-NC-ND, http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial reuse, distribution, and reproduction in any medium, provided the original work is not changed in any way and is properly cited. For permission for commercial reuse, please email: oa@electrochem.org. [DOI: 10.1149/2.0021508eel] All rights reserved.

This paper describes working principles of traditional ladder-type surface acoustic wave (SAW) filter composed by resonators. The simulation model was founded by utilizing Quite Universal Circuit Simulator (QUCS) for a seven stepped SAW filters on substrate of relaxor based ferroelectric single crystals. An extremely large wideband SAW filter of 620 MHz at 1 GHz could be obtained due to large electromechanical coupling factor (K2∼60%) when the substrate is poled along (111) plane, which is presently three times larger than that achieved by conventional piezoelectric material. The band rejection could be improved by adjusting static capacitance ratio of series and parallel arm resonators. In order to optimize overall properties of the ultra-wideband SAW filter, we have modified the structure of a conventional ladder-type filter by adding a resonator to series or parallel arm to form two new notches, which sacrifices some bandwidth, but could achieve large transition band, steep transition zone and also band rejection. Finally, we discussed the influence of quality factor on the insertion loss of the SAW filters.

The cycling performance of LiPF4(C2O4) electrolyte is compared with LiPF6 electrolyte in the presence of several different electrode materials. The cycling of MCMB/LiNi1/3Co1/3Mn1/3O2 and natural graphite/LiFePO4 cells provides very similar performance for both electrolytes. However, MCMB/LiMn2O4 cells have a lower initial reversible capacity with LiPF4(C2O4) electrolytes. A detailed analysis of the surface films on both the cathode and the anode via X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) was conducted. The performance differences are attributed to the anode as opposed to the cathode.

A hierarchical porous carbon with low oxygen content has been prepared by using polystyrene (PS) spheres as template and its structure, composition and performances as anode of lithium ion battery are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, element analysis (EA), electrochemical impedance spectroscopy (EIS), and galvanostatic charge/discharge test. The results obtained from SEM, TEM, XRD, FTIR, and EA indicate that the prepared sample has a well-interconnected pore structure with a pore size of 170 nm and has an oxygen content of 3.3 ± 0.2 wt.%. The low oxygen content of the prepared sample can be ascribed to the low decomposition temperature of the template that was determined by thermal analysis. EIS shows that the prepared sample has lower electrochemical impedance for the lithium insertion/de-insertion than commercial natural graphite and charge/discharge tests show that the battery using the prepared sample as anode exhibits better rate performance than that using the graphite.

Polyethylene (PE)-supported poly(methyl methacrylate-vinyl acetate)-co-poly(ethylene glycol) diacrylate with and without doping nano-Al 2 O 3 , namely P(MMA-VAc)-co-PEGDA/PE and P(MMA-VAc)-co-PEGDA/Al 2 O 3 /PE, are prepared and their performances as gel polymer electrolytes (GPEs) for lithium ion battery are studied by mechanical test, scanning electron microscopy, thermogravimetric analyzer, electrochemical impedance spectroscopy, cyclic voltammetry, and charge/discharge test. It is found that the doping of nano-Al 2 O 3 in the P(MMA-VAc)-co-PEGDA/PE improves the comprehensive performances of the GPE and thus the rate performance and cyclic stability of the battery. With doping nano-Al 2 O 3 , the mechanical and thermal stability of the polymer and the ionic conductivity of the corresponding GPE increases slightly, while the battery exhibits better cyclic stability. The mechanical strength and the decomposition temperature of the polymer increase from 15.9 MPa to 16.2 MPa and from 410 °C to 420 °C, respectively. The ionic conductivity of the GPE is from 3.4 x 10 ―3 S cm ―1 to 3.8 x 10 ―3 S cm ―1 . The discharge capacity of the battery using the GPE with doping nano-Al 2 O 3 keeps 90.9% of its initial capacity after 100 cycles and shows good C-rate performance.

The layered LiNi0.6Co0.2−x Mn0.2Mg x O2 (x=0.00, 0.03, 0.05, 0.07) cathode materials were prepared by a co-precipitation method. The properties of the Mg-doped LiNi0.6Co0.2Mn0.2O2 were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and electrochemical measurements. XRD studies showed that the Mg-doped LiNi0.6Co0.2Mn0.2O2 had the same layered structure as the undoped LiNi0.6Co0.2Mn0.2O2. The SEM images exhibited that the particle size of Mg-doped LiNi0.6Co0.2Mn0.2O2 was finer than that of the undoped LiNi0.6Co0.2 Mn0.2O2 and that the smallest particle size is only about 1 μm. The Mg-doped LiNi0.6Co0.2Mn0.2O2 samples were investigated on the Li extraction/insertion performances through charge/discharge, cyclic voltammogram (CV), and electrochemical impedance spectra(EIS). The optimal doping content of Mg was that x= 0.03 in the LiNi0.6Co0.2−x Mn0.2Mg x O2 samples to achieve high discharge capacity and good cyclic stability. The electrode reaction reversibility and electronic conductivity was enhanced, and the charge transfer resistance was decreased through Mg-doping. The improved electrochemical performances of the Mg-doped LiNi0.6Co0.2Mn0.2O2 cathode materials are attributed to the addition of Mg2+ ion by stabilizing the layer structure.

The novel electrolyte, lithium tetrafluorooxalatophosphate (LiPF4(C2O4)), was investigated with various electrodes (graphite, LiNi1/3Co1/3Mn1/3O2, LiFePO4 and LiMn2O4). The room temperature cycling performance of LiPF4(C2O4) is compared to LiPF6 electrolytes.

A new gel polymer electrolyte (GPE) is reported in this paper. In this GPE, blending polymer of poly(ethylene oxide) (PEO) with poly(vinylidene fluoride-hexafluoropropylene) (P(VdF-HFP)), doped with nano-Al2O3 and supported by polypropylene (PP), is used as polymer matrix, namely PEO–P(VdF-HFP)–Al2O3/PP. The performances of the PEO–P(VdF-HFP)–Al2O3/PP membrane and the corresponding GPE are characterized with mechanical test, CA, EIS, TGA and charge–discharge test. It is found that the performances of the membrane and the GPE depend to a great extent on the content of doped nano-Al2O3. With doping 10 wt.% nano-Al2O3 in PEO–P(VdF-HFP), the mechanical strength from 9.3 MPa to 14.3 MPa, the porosity of the membrane increases from 42% to 49%, the electrolyte uptake from 176% to 273%, the thermal decomposition temperature from 225 °C to 355 °C, and the ionic conductivity of corresponding GPE is improved from 2.7 × 10−3 S cm−1 to 3.8 × 10−3 S cm−1. The lithium ion battery using this GPE exhibits good rate and cycle performances.

Antistatic composites of poly(ethylene terephthalate) (PET) and tetrapod-shaped ZnO whisker (ZnOw), the surface of which was treated with a coupling agent, were prepared by melt-mixing using a twin screw extruder. The structure and morphology of the blends were examined by FTIR and SEM. Antistatic performance and the effect of ZnOw loading levels were investigated. The conductive mechanism of PET/ZnOw composites is presented, which can be classified into tunnel effect, discharging effect at the pinpoint and conductive network. The simple formula of critical volume fraction (vc) for ZnOw forming conductive network is proposed, based on the actual processing conduction. Comparison of the theory value to the experimental data showed a close agreement. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers

A hyper-stoichiometric alloy, La 0.65 Ce 0.28 Pr 0.02 Nd 0.05 Ni 3.9 Co 0.7 Mn 0.34 Al 0.26 (MlB 5.2 ), was prepared by twin-roller rapid quenching process. Its structure and electrochemical properties were characterized by XRD, SEM and constant current charging/discharge cycles, and were compared with those of a stoichiometric alloy, La 0.65 Ce 0.28 Pr 0.02 Nd 0.05 Ni 3.8 Co 0.7 Mn 0.3 Al 0.2 (MlB 5.0 ). Both of the alloys have a typical single-phase hexagonal CaCu 5 -type structure. The cell volume of the hyper-stoichiometric alloy MlB 5.2 is the same size as that of the stoichiometric alloy MlB 5.0 , although its lattice constant c / a is smaller. Better cyclic stability can be reached for MlB 5.2 than MlB 5.0 as negatives of nickel–metal hydride batteries. This improvement in cyclic stability can be ascribed to the slower charge transfer reaction for MlB 5.2 than MlB 5.0 . There is only 11.1% loss of capacity for MlB 5.2 under 2 C discharge rate, 640 mA g −1 , but 20.2% for MlB 5.0 . It is found that there is a lower capacity, a higher polarization and larger reaction resistance at the beginning of cycling for MlB 5.2 than MlB 5.0 .

In order to deepen the understanding of the relationship between fundamental properties (including: microstructure and composition) and photocatalytic performance, four bismuthate compounds, including: LiBiO3, NaBiO3, KBiO3, and AgBiO3, are regarded as research examples in the present work, because they have particular crystal structures and similar compositions. Using density functional theory calculations, their structural, electronic, and optical properties are investigated and compared systematically. First of all, the calculated results of crystal structures and optical properties are in agreement with available published experimental data. Based on the calculated results, it is found that the tunneled or layered micro-structural properties lead to the stronger interaction between bismuth and oxygen, and the weaker interaction between alkaline-earth metal and [BiO6] octahedron, resulting in the feature of multi-band gaps in the cases of LiBiO3, NaBiO3, and KBiO3. This conclusion is supported by the case of AgBiO3, in which the feature of multi-band gaps disappears, due to the stronger interaction between the noble metal and [BiO6] octahedron. These properties have significant advantages in the photocatalytic performance: absorbing low energy photons, rapidly transferring energy carriers. Furthermore, the features of electronic structures of bismuthate compounds are well reflected by the absorption spectra, which could be confirmed by experimental measurements in practice. Combined with the calculated results, it could be considered that the crystal structures and compositions of the photocatalyst determine the electronic structures and optical properties, and subsequently determine the corresponding photocatalytic performance. Thus, a novel Bi-based photocatalyst driven by visible-light could be designed by utilizing specific compositions to form favorable electronic structures or specific micro-structures to form a beneficial channel for energy carriers.