以Mn3O4为锰源合成高性能LiMn2O4正极材料

以Mn3O4为锰源,采用固相反应法,在较低的温度(650℃)制得尖晶石LiMn2O4正极材料。采用X射线衍射(XRD)、扫描电镜(SEM)、循环伏安和恒流充放电等技术对其相组成、微结构和电化学性能进行表征。结果表明该正极材料结晶良好,一次粒径约为150 nm。它的电化学性能,尤其是循环性能,明显优越于在较高温度合成的LiMn2O4。在电流密度为74 mA?g-1时,测得比容量为128 mAh?g-1,在1 480 mA?g-1时,比容量为105 mAh?g-1;在室温、148 mA?g-1充放电200次循环后,容量保持率为93%。     

Excellent supercapacitive performance of a reduced graphene oxide/Ni（OH）2 composite synthesized by a facile hydrothermal route

A reduced graphene oxide/Ni（OH）2 composite with excellent supercapacitive performance was synthesized by a facile hydrothermal route without organic solvents or templates used.XRD and SEM results reveal that the nickel hydroxide,which crystallizes into hexagonal β-Ni（OH）2 nanoflakes with a diameter less than 200 nm and a thickness of about 10 nm,is well combined with the reduced graphene oxide sheets.Electrochemical performance of the synthesized composite as an electrode material was investigated by cyclic voltammetry,electrochemical impedance spectroscopy and galvanostatic charge/discharge measurements.Its specific capacitance is determined to be 1672 F/g at a scan rate of 2 mV/s,and 696 F/g at a high scan rate of 50 mV/s.After 2000 cycles at a current density of 10 A/g,the composite exhibits a specific capacitance of 969 F/g,retaining about 86% of its initial capacitance.The composite delivers a high energy density of 83.6 W·h/kg at a power density of 1.0 kW/kg.The excellent supercapacitive performance along with the easy synthesis method allows the synthesized composite to be promising for supercapacitor applications.     

Nanoscale Ni-B amorphous alloy catalyst supported on carbon nanotubes

Heat treatment of carbon nanotubes （CNTs） was carried out under ammonia atmosphere and then CNTs were modified by Triton x-100 （CNTs-T）. Ni-B amorphous alloy catalysts supported on CNTs and CNTs-T were prepared by impregnation-chemical reduction method. The catalysts were characterized by TEM, ICP, XRD, BET and CO chemisorption, and studied in the acetylene selective hydrogenation. The results show that homogeneous Ni-B amorphous particles with mean size about 10 nm are successfully prepared on CNTs-T. Compared with Ni-B/CNTs, nickel loading of Ni-B/CNTs-T is increased by about 14.6%. Furthermore, the activity and selectivity of Ni-B/CNTs-T are much higher than those of Ni-B/CNTs in the acetylene selective hydrogenation under comparative condition.     

以Mn3O4为原料制备高性能尖晶石LiMn2O4正极材料

本文实验以Mn₃O₄为锰源和Li₂CO₃为锂源，对不同温度制备的尖晶石型LiMn₂O₄的结构和电化学性能进行了分析研究。XRD分析测试表明在不同温度段制得的尖晶石LiMn₂O₄均为纯相；SEM分析测试表明不同温度制得的尖晶石LiMn₂O₄晶粒大小均匀，随着煅烧温度上升LiMn₂O₄晶粒逐渐长大。尖晶石LiMn₂O₄的电化学性能测试结果表明，在650～750℃范围煅烧的尖晶石LiMn₂O₄要优于750℃以上煅烧的样品。     

如何做好外墙外保温系统裂缝的质量控制

1前言 近年来,在国家行政法规和技术标准的推动下,外墙外保温技术正在迅速发展,形成了一批外墙外保温系统定型产品和成套技术。比如EPS（XPS）板薄抹灰外保温系统、胶粉EPS颗粒保温浆料外保温系统、水泥基复合保温砂浆外保温系统等。伴随外保温技术的大量应用,也出现了不少质量问题,这其中最突出、影响最大的就是裂缝防治问题。     

阻燃透光不饱和聚酯树脂和玻璃钢性能的研究

本文介绍了高聚物的燃烧和阻燃机理、塑料和不饱和聚酯树脂的阻燃化方法;研究了阻燃透光不饱和聚酯树脂的性能,着重探讨了阻燃透光不饱和聚酯树脂品种、阻燃剂添加量、固化制度、玻璃钢厚度以及玻璃纤维含量对阻燃透光玻璃钢燃烧性能(氧指数OI)与透光性能的关系。