聚吡咯/氧化石墨复合材料的制备及其电容性能

以氧化石墨为载体,采用木质素磺酸钠作为掺杂剂,氯化铁作为氧化剂,引发吡咯单体在氧化石墨层发生化学原位聚合反应,制备了聚吡咯(PPy)/氧化石墨复合材料。通过XRD、FTIR和SEM分析分别对复合材料的物相组成、结构和微观形貌进行了表征,通过TGA分析研究了复合材料的热稳定性,采用恒电流充放电、循环伏安和电化学阻抗谱等方法测试分析其电化学性能。研究表明:采用化学原位聚合的方法合成的PPy/氧化石墨复合材料具有"层-球"状的"三明治"型微观结构,以便形成良好的导电网络,其结晶度高、排列规整、缺陷少,复合材料中吡咯单体通过N-H键与氧化石墨的含氧官能团发生键合。PPy/氧化石墨复合材料新颖的微观结构和良好的化学键合状态使其表现出优异的电容性能。在电流密度分别为0.5、1.0、2.0和5.0 A/g时的比电容分别为500、460、427和396 F/g;经过1000次恒电流(2.0 A/g)充放电循环后, PPy/氧化石墨复合材料的比电容保持率为97.2%。 

Preparation of polypyrrole/graphite oxide composite and its capacitive properties

Taking the graphite oxide as the supporter, using sodium lignosulphonate as the dopant and ferric chloride as the oxidant, the polypyrrole(PPy)/graphite oxide composite was prepared by the chemical in-situ polymerization of pyrrole monomer in the graphite oxide layers. The phase composition, structure and morphology were characterized by XRD, FTIR and SEM, respectively. The thermal stability of the composite was analyzed by TGA. The electrochemical performance of the composites was examined through galvanostatic charge-discharge, cyclic voltammetry and electrochemical impedance technique. Results show that the PPy/graphite oxide composite synthesized by the chemical in-situ polymerization method is with a kind of "layer-ball" "sandwich" type microstructure so as to form a good conducting network. The synthesized composite is with high crystallinity, neat and less defects. And the pyrrole monomer in the composite materials is bonded with the oxygen containing functional groups of the graphite oxide by the keys of N-H. This kind of novel microstructure modeling of PPy/graphite oxide composite and the perfect chemical key connecting between them confirm it with high capacitance. The specific capacitances of the composites are 500, 460, 427 and 396 F/g at the current density of 0.5, 1.0, 2.0 and 5.0 A/g, respectively. Moreover, after 1000 cycles at the current density of 2.0 A/g, the capacitance retention of the PPy/graphite oxide composite is 97.2%.