Synthesis of carbon microtubules core structure LiFePO4 via a template-assisted method

The carbon microtubules core structure LiFePO₄ is synthesized using a cotton fiber template-assisted method. The crystalline structure and morphology of the product is characterized by X-ray diffraction and field emission scanning electron microscopy. The charge–discharge kinetics of the LiFePO₄ electrode is investigated using cyclic voltammetry and electrochemical impedance spectroscopy. The result shows that the well-crystallized carbon microtubules core structure LiFePO₄ is successfully synthesized. The as-synthesized material exhibits a high initial discharge capacity of 167 mAh g^?1 at 0.2 C rate. The material also shows good high-rate discharge performance and cycling stability, about 127 mAh g^?1 and 94.7 % capacity retention after 100 cycles even at 5.0 C rate.     

Controllable length adjustment of polyaniline particle with temperature sensitive block copolymer as template

Although the diameter of conductive polymer nanoparticles can be controlled effectively, the uniformity of particle length is still very challenging. In this study, with the temperature‐sensitive block copolymer PS₁₁₁‐b‐PNIPAM₁₁₄ as the template, the morphology and size of polyaniline (PANI) particles had been controllably adjusted through the change of temperature. Additionally, the electrochemical performance of each sample was investigated. After PS₁₁₁‐b‐PNIPAM₁₁₄ was synthesized through the reversible addition‐fragmentation chain transfer radical polymerization (RAFT), with its vesicular micelle as the “template”, the PANI particles with uniform length distribution were prepared successfully at 40°C. The average length of PANI particles after template removal was 254.07 nm with a short tail distribution, which was closer to the average than the standard normal distribution. Electrochemical results of PANI showed that it had good electrochemical activity with fast charge and discharge ability. And, with the current density of 1 A·g^?1, its discharge‐specific capacitance could reach up to 805.61 F·g^?1.     

基于四苯基卟啉铁敏感膜的玻璃光波导传感器对乙二胺的响应特性

为检测食品变质过程中产生的乙二胺气体,采用Alder法合成了四苯基卟啉和四苯基卟啉铁化合物,通过核磁(~1H NMR)、场发射扫描电子显微镜(FE-SEM)、红外光谱(IR)、紫外可见光谱(UV-Vis)等手段对其进行表征,并以四苯基卟啉铁作为敏感试剂,利用旋涂法制备了四苯基卟啉铁薄膜/K+交换玻璃光波导传感元件,对多种气体进行检测。结果表明:该传感元件对乙二胺气体具有较好的选择性响应,较高的灵敏度,在1×10~(-10)~1×10~(-4)(V/V_0;V:被检测气体体积,V0:空气体积)体积比范围内,体积比与输出光强度间线性关系良好(R=0.9940),响应时间和恢复时间分别为3 s和11 s,信噪比S/N=4.8,RSD=0.5%(V/V_0=1×10~(-7))。平行试验中,其结果也具有良好的线性关系(R=0.9985),证明该传感元件对乙二胺气体检测的准确性。该类传感元件在食品品质检测方面有很好的应用与发展。     

Characterization of the Optical and Gas Sensitivities of a Nickel-Doped Lithium Iron Phosphate Thin Film

The influence of heat-treatment temperature on the optical properties (refractive index, transmittance, and attenuation) and gas sensitivities of nickel-doped lithium iron phosphate (LiFe_0.99Ni_0.01PO₄) thin films were discussed. LiFe_0.99Ni_0.01PO₄ was synthesized in one step using hydrothermal methods and fixed to tin-diffused glass as a sensing film by spin-coating before calcination at different temperatures. The obtained thin films were characterized by refractive index, thickness, attenuation, and porosity, as well as gas sensing performances for benzene, toluene, and xylene. The experimental results indicated that the LiFe_0.99Ni_0.01PO₄ thin films dried at 450°C displayed higher refractive indices, good transparency, and less attenuation; thus, the resulting sensor of a LiFe_0.99Ni_0.01PO₄ thin film/tin-diffused optical wave-guide exhibited a greater response to xylene in the concentration range of 0.1–1000?ppm.