Polyaniline nanosheets templated from aniline‒acid precipitates and their electrochemical performance for flexible supercapacitor

The simple synthesis of two-dimensional (2D) polyaniline (PANI) structures remains a big challenge owing to the intrinsic growth of PANI chains into one-dimensional structures and the curling of the PANI chains into spherical particles. In this contribution, we report on the simple synthesis of PANI nanosheets by oxidizing aniline–acid precipitates with ammonium persulfate (APS) through a chemical oxidation polymerization method. The tested acids include methylene disulfonic acid, sulfuric acid, benzoic acid, oxalic acid, p-toluenesulfonic acid, hydrochloric acid, and acetic acid. The aniline–acid precipitates serve as separation-free templates for producing PANI nanosheets. The yield, oxidation level, electronic conductivity, conjugation length, and thickness of the PANI nanosheets can be tuned by controlling the molar ratio of aniline/APS. The electrochemical performance of PANI nanosheets-based symmetric supercapacitors was examined at the temperature ranging from room temperature to –60 °C. The PANI nanosheets with relatively high specific surface area rather than the oxidation level manifest superior electrochemical performance.