Gravity-assisted synthesis of micro/nano-structured polypyrrole for supercapacitors

A highly electroactive polypyrrole film (GA-hPPy) with micro/nano-structured horn-like arrays is synthesized by a pulse potentiostatic method with the assistance of gravity. Compared with the conventional cauliflower-like PPy (cPPy) that is synthesized without gravity assistance, GA-hPPy exhibits horn-like morphology in good ordering and uniform size, which leads to remarkably high ionic and electronic conductivity, as confirmed by apparent diffusion coefficient and limit diffusion coefficient. It presents great specific capacitance up to 360 F g⁻¹ at the scanning rate of 10 mV s⁻¹ and ultrafast charging/discharging capability, with a specific capacitance of 208 F g⁻¹ at the scanning rate of 1000 mV s⁻¹. Its cycling performance is validated to be stable as 88.2% of capacitance held after 10,000 continual cycles. With these distinguishing properties, GA-hPPy is promising to be an excellent active material for supercapacitors.