电接枝聚乙烯亚胺改性碳纤维电极电化学性能及其电场响应研究

碳纤维电极表面氨基改性可以显著提高其电化学性能和电场响应性能。通过高温氧化和电化学接枝相结合的方法,在碳纤维表面接枝不同分子量（0.6K、1.8K、10K）聚乙烯亚胺分子来调控电极/海水界面双电层结构。实验发现,长分子链之间因氢键更强的相互作用更容易穿插交叠,形成稳定双电层结构。结果表明：PEI-10K的性能最佳,其比电容达到12.8 F·g^-1,电荷转移电阻和低频容抗显著降低;配对电极的电位漂移量仅为0.05 mV/d,电极自噪声降为2.61 nV/sqrt(Hz),并且可以响应1 mHz、0.03 mV/m的低频弱电场信号;改性后碳纤维电极的响应灵敏度、准确度得到了显著提高,可用于制备高性能海洋电场传感器,提高水下电场探测能力。     

Enhanced electrochemical performance in lithium ion batteries of a hollow spherical lithium-rich cathode material synthesized by a molten salt method

A high voltage layered Li1.2Ni0.16Co0.08Mn0.56O2 cathode material with a hollow spherical structure has been synthesized by molten-salt method in a NaCI flux. Characterization by X-ray diffraction and scanning electron microscopy confirmed its structure and proved that the as-prepared powder is constituted of small, homogenously sized hollow spheres （1-1.5 μm）. The material exhibited enhanced rate capability and high first cycle efficiency due to the good dispersion of secondary particles. Galvanostatic cycling at different temperatures （20, 40, and 60 ℃） and a current rate of 2 C （500 mA.g-1） showed no significant capacity fade.     

碳包覆空心Fe3O4纳米粒子作为锂离子电池负极材料的电化学性能研究

以二茂铁为铁源,石油渣油为碳源,通过加压热解和空气氧化制备了碳包覆空心Fe3O4纳米粒子。采用X射线衍射(XRD)、透射电镜(TEM)以及高倍透射电镜(HRTEM)等测试方法对样品的形貌和结构进行表征。采用恒流充放电和交流阻抗方法测试碳包覆空心Fe3O4纳米粒子作为锂离子电池负极材料的电化学性能。在电流密度为0.2mA/cm2时,首次放电比容量高达1294.7mAh/g,30次循环之后其放电比容量为392.1mAh/g;电流密度为1mA/cm2时,首次放电比容量为216.3mAh/g,30次循环之后其放电比容量为113mAh/g。     

Hierarchical hollow Li4Ti5O12 urchin-like microspheres with ultra-high specific surface area for high rate lithium ion batteries

Large specific surface area is critical for Li4Ti5O12 to achieve good rate capacity and cycling stability, since it can increase the contact area between electrolyte/ electrode and shorten the transport paths for electrons and lithium ions. In this study, hierarchical hollow Li4Ti5O12 urchin-like microspheres with ultra-high specific surface area of over 140 m2·g^-1 and diameter more than 500 nm have been successfully synthesized by combining the versatile sol-gel process and a hydrothermal reaction, and exhibit excellent electrochemical performance with a high specific capacity of 120 mA-h.g-1 at 20 C and long cycling stability of 〈 2% decay after 100 cycles. Ex situ electron energy loss spectroscopy （EELS） analysis of Li4Ti5O12 microspheres at different charge-discharge stages indicates that only a fraction of the TP＊ ions are reduced to Ti3＋ and a phase transformation occurs whereby the spinel phase Li4TisO12 is converted into the rock-salt phase Li7Ti5O12. Even after 100 cycles, the oxidation-reduction reaction between Ti3＋ and Ti4＋ can be carried out much more effectively on the surface of Li4Ti5O12 nanosheets than on commercially available Li4Ti5O12 particles. All the results suggest that these Li4Ti5O12 microspheres may be attractive candidate anode materials for lithium ion batteries.     

碳酸氢钠改性Ag/AgCl海洋电场电极的研制及其性能

为提高Ag/AgCl电极性能,通过在粉压型Ag/AgCl电极中添加一定含量的碳酸氢钠(NaHCO3)发泡剂,利用电极在高温烧结成型过程中NaHCO3会发生分解反应产生CO2气体的性质,研制出高孔隙率的Ag/AgCl新型海洋电场电极.进一步基于综合热分析和称重法测试结果,研究NaHCO3-Ag/AgCl电极的制备工艺参数...     

水合肼掺氮改性碳纤维电极电化学及电场响应性能

碳纤维表面氮掺杂改性可望提高其电化学性能和电场响应性能.以水合肼为氮源改性粘胶基碳纤维,制备新型海洋电场电极,并探究改性前后电极电化学性能以及电场响应性能变化.结果表明:改性碳纤维电极电化学性能以及电场响应性能显著提高;水合肼高温掺氮处理样品性能最佳,其比电容达到102.5 F/g,为空白组的18.99倍;电荷转移电阻...     

碳纤维正极添加剂对阀控铅酸蓄电池性能的影响

本文采用两种比表面积不同的碳纤维,取代原有正极铅膏配方中的炭材料作为正极添加剂。采用手工涂膏方式,制备12 V/12 Ah阀控式铅酸蓄电池。并研究了正极板化成情况和蓄电池电化学性能。结果表明,比表面积较大的碳纤维更有利于提高蓄电池正极性能。随着碳纤维含量的提高,电池放电时间反而缩短。碳纤维在正极铅膏中最佳添加量为0.5‰。适量碳纤维的添加,对电池化成是有利的。循环伏安测试表明,添加碳纤维会影响正极电化学电位和析氧量。