Dynamically evolving 2D supramolecular polyaniline nanosheets for long-stability flexible supercapacitors

Highly pseudocapacitive conducting polyaniline (PANI) shows promising applications in flexible supercapacitors while suffer from low rate-capability and structural instability. The charging-discharging process with strong stress–strain behavior will unavoidably lead to the rapid break of PANI, badly restricting the cyclic stability of PANI-based supercapacitors. Herein, we employ a dynamically evolving emulsion polymerization strategy to elaborately construct two-dimensional (2D) secondary supraparticles polyaniline (ss-PANI) for greatly enhancing cycling stability of PANI-based supercapacitors. With dynamically evolving crosslink of aniline monomers and 1,4-phenylenediboronic acid, nanoparticles are firstly formed with the micelle action followed by demulsifying to transform into discrete platelets and further into 2D nanosheets via intermolecular hydrogen bonding. Ascribing to its excellent volume durability and the intermolecular hydrogen bonding effect, the greatly improved strain energy can efficiently restrict the volume change during repeatedly charging/discharging process. This 2D ss-PANI-based supercapacitors show a remarkable cycling stability of 93.9% capacitance retention over 10,000 cycles, which is far better than the previously reported PANI-based supercapacitors. Besides, the secondary supraparticles 2D structure endows PANI with rapid mass transfer rate that guarantees high specific capacitance (378 F g-1) and high rate-capability. Undoubtedly, this research can guide the design of electrochemically dynamics-enhanced conducting polymers for the high-stability flexible supercapacitors as well as the portable energy storage devices.