Orderly Paa Templates Prepared Pani Nano Array And Its Application In Electrochemical Capacitors

Polyaniline (PANI) is one of the most promising electrode materials for supercapacitor. It will be more widely used by being fabricated into one-dimensional nanostructure through a porous anodic alumina (PAA) template. Based on the preparation of PAA templates with different morphologies, one-dimensional nano PANI was successfully synthesized in this work by electrochemical polymerization, and its electrochemical performance was also analyzed.Firstly, the PAA templates were fabricated in the oxalic acid and phosphoric acid aqueous solutions, respectively. And the influence of anodic oxidation conditions on templates was studied. The results show that a PAA template with straight channels can be quickly prepared in the oxalic acid by a constant current high-fie Id anodization, and more ordered template can be obtained by a two-step anodization. The PAA templates fabricated in phosphoric acid by high voltage (200V or160V) anodizations have larger interpore distances but poor regularity. A PAA template with serrated channels can be synthesized by a low voltage (60V) anodization in phosphoric acid. In addition, the removal of barrier layer and stripping process of PAA template were also investigated in this work. The results show that both the progressive reducing voltage method and the anodization of double-layer composite aluminum foil which is first proposed in this paper can achieve the purpose.Secondly, the electrochemical synthesis process of common PANI film was studied, followed by the analysis of morphology and electrochemical properties. The results show that both cyclic voltammetry (CV) and constant voltage method can be used for the electrochemical deposition of PANI, and the morphologies of PANI fabricated by these two methods are identical. It is worth to note that performance degradation will arise if the preparing process lasts too long due to the severe dynamics relaxatioa The performances of PANI in different electrolytes show that the presence of protons plays a key role in the capacitance performance of PANI. The PANI has a continuously decreasing capacitance in neutral solution, which can be recovered when re-doped in acid again. Moreover, the alkaline electrolyte has an irreversible damage to the structure of PANI.Finally, one-dimensional nano PANIs in oxalic acid templates and high-voltage (160V) phosphoric acid template were obtained by a stainless steel composite method and an in situ gold-plated method, respectively. But the preparation failed in high-voltage (200V) phosphoric acid template whose barrier layer was unable to remove, and in low-voltage phosphoric acid template due to its weak structure. The electrochemical properties of one-dimensional nano PANIs were also investigated. The results show that, compared to the common PANI film, one-dimensional nano PANI exhibits bwer dynamics relaxation; higher specific capacitance, energy density and power density; and lower charge transfer resistance; which indicates that the one-dimensional nano PANI is expected to find widespread applications in electrochemical capacitors.