This paper involves preparation of four different crystal phases (delta, gamma, alpha and lambda) of MnO2 by redox, solid reaction, hydrothermal routes and delithiation of LiMn2O4, respectively. The obtained MnO2 samples have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and the Brunauer-Emmett-Teller (BET) method for micro-structural, morphological and porosity studies. Cyclic voltammetric and galvanostatic tests were carried out to evaluate their capacitive properties in an anti-freezing aqueous electrolyte at different operating temperatures ranging from 25 to -35 degrees C. The delta-MnO2 prepared by a redox method exhibits the best electrochemical performances when conducted either in the single electrode tests (from 174.7 to 148.6 F g(-1)) or in the capacitor measurements (from 47.4 to 42 F g(-1)) as the operating temperature decreased from 25 degrees C down to the low temperature of -35 degrees C. Moreover, electrochemical impedance spectroscopy has been investigated and the activation energy values of different impedance components have been analyzed. It has been discovered that the operation temperature has more effect on the charge transfer resistance than diffusion resistance. To some degrees, these results have guiding significance for the low-temperature applications of manganese oxides-based electrochemical capacitors. (C) 2014 Elsevier Ltd. All rights reserved.

通过Friedel-Crafts酰基化反应制备二茂铁（Fc）功能化氧化石墨烯材料,利用透射电镜、傅里叶变换红外光谱和X-射线衍射对该复合物的形貌和结构进行了表征。将其滴涂到玻碳电极（GCE）表面并用Nafion膜固定,进行电化学还原,得到电化学还原氧化石墨烯复合材料修饰电极（Fc/ERGO/GCE）。此修饰电极对多巴胺的氧化还原具有良好的催化性能,在循环伏安曲线的0.2 V附近出现一对多巴胺的可逆氧化还原峰。差示扫描伏安法（DPV）峰电流大小与多巴胺浓度在0.4~300μmol/L范围内呈良好的线性关系（R2=0.9998）,检出限为0.08μmol/L。用于检测人体尿液中的多巴胺含量,加标样品的回收率在92.5%~105.0%之间,相对标准偏差小于5%（n=5）,表明制备的Fc/ERGO/GCE可用于实际样品中DA的检测。

La-doped Li3V2(PO4)3/C cathode materials are synthesized by a sol–gel-assisted, low-temperature sintering process. The resulting cathode has a stable specific capacity of 160 mA h g−1at 0.2 C, and retained a stable capacity of up to 116 mA h g−1at 5 C.

One of the primary challenges in the development of a breakthrough lithium ion battery technology is to identify a composition that can effectively provide high power densities as well as high energy densities. Conventional graphitic anodes are considerably limited in this regard, owing to a limited charge storage capacity and constrained ionic and electrical conductivity. In this work, we report the use of a facile, scalable and low-cost Far Infrared (FIR) reduction strategy for the synthesis of graphene anodes as an alternative to conventional graphitic anodes. FIR irradiation was found to effectively reduce graphene oxide to graphene in under 3 min and displayed exceptional charge/discharge rates and charge storage capacities when used as an anode in lithium ion batteries. The binder-free FIR graphene anodes provided a very high reversible capacity of ~1016 mA h/g at a C-rate of ~1 C. Further, the FIR-reduced graphene anodes displayed impressive rate capabilities, delivering remarkably steady capacities as high as ~181 mA h/g at a C-rate of ~40 C over 1000 charge/discharge cycles, corresponding to an average power density of ~14 kW/kg.

The modification techniques of applying carbon coating on particle surface and doping vanadium at Fe site were applied to make the LiFePO4 cathode materials achieve high rate performance in lithium ion batteries. To design and synthesize these LiFe(1−x)V x PO4/C (x = 0, 0.02, 0.05, or 0.08) composites, an aqueous solution–evaporation method was taken, in which every kind of raw material was distributed at a high degree of uniformity. The LiFe0.95V0.05PO4/2.57 wt% C composite displayed the best electrochemical performances. At rates of 0.1, 0.5, 2, 5, and 10 C (1 C = 170 mAg−1), it delivered a discharge capacity of 157.8, 156.9, 149, 139.6, and 130.1 mAh g−1, respectively. The composite exhibited perfect cycle stabilities as well, maintaining 100 % (0.5 C), 99.7 % (2 C), 98.9 % (5 C), and 96.6 % (10 C) of the first discharge capacity after 100 cycles at different rates, respectively.

We report a novel far-infrared (FIR) thermal reduction process to effectively reduce graphene oxide films for supercapacitor electrode applications. The binder-free graphene oxide films used in this study were produced by electro-spray deposition of a graphene oxide colloidal solution onto stainless steel current collectors. The reduction of graphene oxide was performed using a commercial FIR convection oven that is ubiquitous in homes for cooking and heating food. The reduction process incorporated a simple, one-step FIR irradiation carried out in ambient air. Further, the FIR irradiation process was completed in ∼3min, wherein neither special atmosphere nor high temperature was employed, resulting in an economic, efficient and simplified processing technique. The as-produced FIR graphene electrode gave a specific capacitance of ∼320F/g at a current density of ∼0.2A/g with less than 94% loss in specific capacitance over 10,000 charge/discharge cycles. This is one of the best specific capacitances reported for all-carbon electrodes without any additives. Even at ultrafast charge/discharge rates (current densities as high as ∼100A/g), the FIR graphene electrode still delivered specific capacitances in excess of 90F/g. The measured energy and power densities of the FIR supercapacitors were found to be ∼3–6 times higher than commercial (activated carbon) supercapacitor devices. This excellent electrochemical performance of the FIR graphene coupled with its ease of production (in air at low temperatures) using a commercial home-use FIR convection oven indicates the significant potential of this concept for large-scale commercial electrochemical supercapacitor applications.

The solubility data of lithium bis(oxalate)borate (LiBOB) were measured in six different solvents using the synthetic method and laser monitoring technique at temperatures ranging from (293.15 to 363.15) K under atmospheric pressure. The experimental solubilities of LiBOB in different solvents were correlated by the modified Apelblat equations. It is found the calculated solubility data show good consistency with the experimental values. On this basis, some thermodynamic parameters of LiBOB in different solvents, such as dissolution enthalpy, dissolution entropy, and dissolution Gibbs free energy, are also calculated. These results concerning the solubility of LiBOB in different solvents will provide fundamental data in the commercial application of LiBOB.

We present a new method for specific detection of oxytetracycline (OTC) at nanomolar concentrations based on a microfabricated cantilever array. The sensing cantilevers in the array are functionalized with self-assembled monolayers (SAMs) of OTC-specific aptamer, which acts as a recognition molecule for OTC. While the reference cantilevers in the array are functionalized with 6-mercapto-1-hexanol SAMs to eliminate the influence of environmental disturbances. The cantilever sensor shows a good linear relationship between the deflection amplitude and the OTC concentration in the range of 1.0-100 nM. The detection limit of the cantilever array sensor is as low as 0.2 nM, which is comparable to some traditional methods. Other antibiotics such as doxycycline and tetracycline do not cause significant deflection of the cantilevers. It is demonstrated that the cantilever array sensors can be used as a powerful tool to detect drugs with high sensitivity and selectivity.

To enhance the electrochemical performance of LiFePO4/C, Na and V have been co-doped in cathode material of the lithium ion batteries. A series of Na and V doped samples Li0.97Na0.03Fe(1-x)VxPO4/C (x=0, 0.01, 0.03, 0.05) cathode materials are synthesized by solid state method. Results show that the Li0.97Na0.03Fe0.97V0.03PO4/C exhibited the best electrochemical performances.

The LiFePO4/C samples have been synthesized via an aqueous solution-evaporation route with LiH2PO4, FeC2O4.2H2O as raw materials and citric acid as a carbon source. X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to analyze structure and morphology of the samples. The electrochemical performances of the LiFePO4/C cathodes were characterized by charge/discharge cures and electrochemical impedance spectroscopy (EIS). The results show that the LiFePO4/C sample, calcined at 700 °C and contained 3.03% (by mass) carbon, exhibited a highly pure crystalline phase with the primary particles sizes of 100 nm. The surfaces of those particles were covered by a carbon layer of 5 nm in thickness. At the rates of 0.5C, 2C, 5C, and 10C, where 1C corresponds to 170 mAh·g-1, the discharge capacities of 148.2, 142.7, 127.4, and 108.5 mAh·g-1, were delivered, respectively, with the perfect cycling stabilities.

To enhance the electrochemical performance of LiFePO4/C, Na and V have been co-doped in cathode material of the lithium ion batteries. A series of Na and V doped samples Li0.97Na0.03Fe(1-x)VxPO4/C (x=0, 0.01, 0.03, 0.05) cathode materials are synthesized by solid state method. Results show that the Li0.97Na0.03Fe0.97V0.03PO4/C exhibited the best electrochemical performances.

An amine-Fe3O4 modified glassy carbon (GC) electrode was constructed for detecting Pb(II) ions in wastewater. The electrode was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Square wave anodic stripping voltammetry (SWASV) was used to detect the Pb(II), and the detection limit of Pb(II) was 0.15 mu M. The sensitivity of the electrode to detect Pb(II) was about 10.07 mu A/mu M, with a correlation coefficient of 0.991, which was approximately 10 times bigger than that of a pure Fe3O4 modified electrode. The electrode also showed good selectivity and stability. This results indicated that the amine-magnetite material could have some potential applications in heavy metal ions detection in wastewater.

Lithium vanadium phosphate[Li3V2(PO4)3 ]is one of the new type of cathode materials for lithium-ion batteries,it has a significant potential application,especially in the research and development of the large capacity power lithium-ion battery.According to the research,lithium vanadium phosphate has the same discharge flat plateaus and capacity density as lithium cobalt oxide[LiCoO2 ],and has far superior thermal stability as well as safety performance to LiCoO2,LiMn2O4,LiFePO4.Furthermore,compared with LiFePO4,higher Li-ion diffusion coefficient,charge-discharge voltage plateau(3.6 V,4.1 V and 4.6 V),and capacity density(2 330 mWh/cm3 after C-doped) are owned by Lithium vanadium phosphate.Therefore,the recent related researches on enhancing the properties of lithium-ion of Li3V2(PO4)3 such as carbon-coating process and doping were reviewed in this paper,the crystal structure of Li3V2(PO4)3,charge/discharge mechanism and properties were also introduced.

In this paper, a series of Ce-doped Li3V2(PO4)(3)/C composite cathode materials for Li-ion batteries were synthesized by a facile and fast microwave assisted sol-gel route. The investigation of the influence of Ce doping on the structural and electrochemical characteristics of Li3V2(PO4)(3)/C shows that the resulting composite exhibits smaller particle size, lower electron-transfer resistance, and faster lithium ion migration, which are attributed to improved lithium ion transfer by the Ce doping. At low charge/discharge rates, the Ce-doped Li3V1.98Ce0.02(PO4)(3)/C composite delivers a stable specific capacity of similar to 170 mAh g(-1) for over 100 cycles. At high rates (e.g. 10C), the Ce-doped composite is still able to deliver stable capacities of up to similar to 120 mAh g(-1) which is similar to 60% greater than its un-doped counterpart. (c) 2013 Elsevier B.V. All rights reserved.

We report a simple and sensitive method for label-free detection of single-stranded DNA-binding protein (SSBP) based on an array of microfabricated cantilevers. The single-stranded DNA (ssDNA) was immobilized on the surface of the sensing cantilevers to detect SSBP, while the reference cantilevers were modified with 6-mercapto-1-hexanol to detect any unwanted cantilever deflection. The differential deflection signals that reveal specific SSBP–ssDNA binding have been found to depend on the SSBP concentration. Using the cantilever array sensor we can detect SSBP in the concentration range from 0.01 to 7μgmL−1. Other proteins, such as thrombin or bovine serum albumin induced no significant deflection of the cantilevers. Our results show the potential for the application of cantilever array sensor system as a powerful tool to detect proteins with high sensitivity and specificity.

A series of new room temperature molten salt electrolyte based on lithium oxalyldifluoroborate (LiODFB) and 2-Oxazolidinone (C3H5NO2, OZO) for EDLCs were synthesized by a facile and fast route. The investigation of the electrochemical characteristics of LiODFB-OZO molten salt electrolytes and the evaluation of LiODFB-OZO complex as electrolyte for EDLCs shows that the resulting molten salt exhibits excellent thermal stability, high ionic conductivity (up to similar to 12.8 mS cm(-1)), a wide electrochemical stability window (similar to 3.8 V) and lower electron-transfer resistance (similar to 4.8 Omega). The EDLCs with the LiODFB-OZO complex electrolyte can be charged up to 3.0 V. At 30 degrees C, the EDLCs with LiODFB-OZO complex electrolyte based on activated carbon electrodes deliver a stable specific capacitance of similar to 83.9 F g(-1); At similar to 70 degrees C, they can deliver stable capacities of up to similar to 106.1 F g(-1) (current density, 1 mA cm(-2)). It is reasonable to assume that LiODFB-OZO complex system has some advantages as electrolyte for EDLCs with high energy density and high-power density, especially at elevated temperatures.

Mesoporous manganese oxides (MnO2) were synthesized via a facile chemical deposition strategy. Three kinds of basic precipitants including sodium carbonate (Na2CO3), sodium bicarbonate (NaHCO3), and sodium hydroxide (NaOH) were employed to adjust the microstructures and surface morphologies of MnO2 materials. The obtained MnO2 materials display different microstructures. Great differences are observed in their specific surface area and porosity properties. The microstructures and surface morphologies characteristics of MnO2 materials largely determine their pseudocapacitive behavior for supercapacitors. The MnO2 prepared with Na2CO3 precipitant exhibits the optimal microstructures and surface morphologies compared with the other two samples, contributing to their best electrochemical performances for supercapacitors when conducted either in the single electrode tests or in the capacitor measurements. The optimal MnO2 electrode exhibits a high specific capacitance (173 F g–1 at 0.25 A g−1), high-rate capability (123 F g−1 at 4 A g−1), and excellent cyclic stability (no capacitance loss after 5,000 cycles at 1 A g−1). The optimal activated carbon//MnO2 hybrid capacitor exhibits a wide working voltage (1.8 V), high-power and high-energy densities (1,734 W kg−1 and 20.9 Wh kg−1), and excellent cycling behavior (93.8 % capacitance retention after 10,000 cycles at 1 A g−1), indicating the promising applications of the easily fabricated mesoporous MnO2 for supercapacitors.

Carbon coated LiFePO4 cathode materials were successfully synthesized by heating the precursors of FePO4@PAn (polyaniline) and equimolar LiOH·H2O under Ar flow. We demonstrated a method that could precisely control the carbon shell in a single reaction step. The precursors of FePO4@PAn were prepared by in situ polymerization of aniline and precipitation of FePO4 in one pot in the presence of hydrogen peroxide as oxidizer. In the obtained core–shell cathode composite, the LiFePO4 core phase was crystalline while the carbon shell had the thickness of several nanometers. The optimized cathode material exhibited satisfactory rate and cycle performance, which virtues are quite suitable for power lithium ion batteries.

原子力显微镜被广泛应用于生物研究领域,基于原子力显微镜的单分子力谱可以在单分子、单细胞水平上研究生物分子内和分子间的相互作用。本文介绍了原子力显微镜单分子力谱在生物分子间相互作用、蛋白质去折叠、细胞表面生物分子、细胞力学性质和基于单分子力谱成像等研究中的最新进展。