Abstract:

Directly in-situ growing an ordered array of nanostructures on a conductive support electrode could improve Faradaic reactions for charge storage in supercapacitor electrode materials and solve the “dead volume”limitation for high-performance pseudocapacitor electrodes. This article reported the in-situ electrochemical preparation of ordered polypyrrole (PPy) nanoarrays on the surface of untreated fluorine doped tin dioxide (FTO) conductive glass (PPy/FTO) to construct a hierarchical structure composed of ordered electroactive polymer nanoarrays on a simple electrode. The morphology and charge storage properties of the PPy/FTO electrode were studied by scanning electron microscopy, transmission electron microscopy, cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy. The ordered PPy/FTO nanoarrays electrode exhibited an intrinsic specific capacitance of 120F/g at a current density of 1A/g. At a current density of 5A/g, it could maintain a specific capacitance of 52%. After 1000 cycles of charge and discharge in neutral LiCl aqueous electrolyte, the capacitance retention rate of the ordered PPy/FTO nanoarray electrode was 41.1%. It was attributed to that the intrinsic PPy nanoarrays were more prone to mechanical fracture due to the expansion and contraction of molecular chains during repeated charge and discharge cycles, which reduced the cycling stability of the electrode material. This study provided an idea for the preparation of conductive polymer nanoarrays structure and also elucidated the drawbacks of intrinsic conductive polymer nanostructures as electrode materials, providing data support for the preparation of conductive polymer composite electrode materials.

Key words: conductive glass, polypyrrole, nanoarrays, electrochemical performance, electrode materials

摘要：

导电支撑电极上原位生长有序纳米结构，可以加改善级电容器电极材料中法拉第反应进行电荷存储，并解决高性能赝电容器电极“死体积”限制。本文报道了在未经任何处理的掺氟二氧化锡（FTO）导电玻璃表面上，利用原位电化学沉积法制备有序聚吡咯（polypyrrole，PPy）纳米棒阵列（PPy/FTO），构建简单电极上有序电活性聚合物纳米阵列结构。通过扫描电子显微镜、透射电子显微镜、循环伏安、恒电流充放电和电化学阻抗谱研究了PPy的形态和电荷存储性能。有序PPy/FTO纳米阵列电极在1A/g电流密度下，本征真实比电容为120F/g；电流密度为5A/g下其可以保持52%的比电容。有序PPy/FTO纳米阵列电极在中性 LiCl水溶液电解液中循环充放电1000次后，电容保持率仅为41.1%，这是因为本征PPy纳米阵列在循环反复充放电过程中，容易发生分子链的膨胀与收缩而产生机械断裂，降低了电极的循环稳定性。本文为导电聚合物阵列结构的制备提供了思路，同时也阐明本征导电聚合物纳米结构作为电极材料的缺点，为导电聚合物复合电极材料的制备提供数据支撑。

关键词: 导电玻璃, 聚吡咯, 纳米阵列, 电化学性能, 电极材料