Remarkably enhanced performances of polyaniline/electrochemically surface-treated graphite electrodes with optimal charge transfer pathways for flexible supercapacitor application

We propose a strategy to enhance the electrochemical performances of electrodes by optimizing charge transfer pathways at the current collector/electroactive material interface. A facile method is developed for electrochemical surface treatment of graphite, and the obtained electrochemical surface-treated graphite is utilized as substrate for electropolymerization of polyaniline, which facilitates the construction of high-quality electrical links at the interface of polyaniline and electrochemical surface-treated graphite. Effect of galvanostatic and potentiostatic polymerization on electrochemical properties of polyaniline electrodes is also examined. Electrochemical measurements indicate that the potentiostatically polymerized polyaniline electrode has superior supercapacitive performances. In particular, polyaniline/electrochemical surface-treated graphite electrode exhibits remarkably enhanced electrochemical properties in comparison with polyaniline/graphite electrode, which can be ascribed to the optimized charge transfer pathways at current collector/electroactive material interface for the former. Polyaniline/electrochemical surface-treated graphite electrode achieves a high specific capacitance of 437.9 mF cm−2 at 0.5 mA cm−2. Moreover, the polyaniline/electrochemical surface-treated graphite electrodes are used to assemble a flexible solid-state supercapacitor. The device demonstrates high flexibility, superior supercapacitive performances, and good cycling stability, which holds great promise for use in flexible electronics.