Abstract:

Conductive polymer polyaniline (PANI) has many advantages, such as large theoretical capacitance, low preparation cost, and ease of synthesis on a large scale. However, the ion transport layer of pure PANI has a compact structure, limiting its application in practice. Herein, the nanocomposites based on inorganic hollow tubular halloysite and conductive polymer polyaniline were prepared by chemical oxidation polymerization with a simple process and low cost. Furthermore, the composites were poured on the graphene electrode to prepare a highly flexible supercapacitor electrode. In analyzing the product's microscopic morphology, it can be observed that polyaniline is uniformly coated on the wall of the halloysite tube, forming a hierarchical core-shell structure. Based on this, the effective contact area between the electrode material and the electrolyte is significantly increased. The resulting halloysite/polyaniline electrode shows an ultra-high capacitance value of 446.1 F/g at a current density of 1 A/g. Even being charged and discharged at an ultra-high current density of 10 A/g, it still has good rate performance and cycle stability and can retain 90.5% of the initial capacitance value after 1600 cycles. In addition, due to the π-π stacking effect between the graphene substrate and PANI, PANI can tightly adhere to the graphene electrode during the repeated bending process, thus obtaining ultra-high bending resistance (keeping 90.2% after 5000 bending cycles). Therefore, the electrode prepared by this method can exhibit excellent electrochemical performance, providing a reference for preparing highly flexible supercapacitors based on conductive polymers.

Key words: graphene electrode, halloysite, polyaniline, layered core-shell structure, flexible capacitor electrode