Scalable Flowing Polymerization and Enhanced Capacitive Properties for Core–Shell Structured Composite Nanofibers toward Highly Efficient Charge Storage in Neutral Electrolytes

Abstract

With the rapid development of portable and wearable devices, the first priority should be given to safety, and furthermore, more attention needs to be paid to polymeric supercapacitors operating in neutral aqueous electrolytes. As a kind of cost-efficient and high-performance electrode materials, core–shell polyaniline (PANi)/polypyrrole (PPy) composite nanofibers are constructed continuously through flowing polymerization in totally aqueous solution without any surfactants and special templates. Moreover, the influences of PANi nanofibers obtained in three different flowing configurations on the growth of the PPy shell and capacitive behaviors of the composite nanofibers are discussed. It is found that significant enhancement on charge storage ability of the composite nanofibers in neutral electrolyte could be achieved, benefiting from the formation of a more compact PPy shell and strong synergistic interaction between the PANi core and PPy shell. The maximal specific capacitance of 670.0 F g–1 was obtained at the current density of 1 A g–1 in Na2SO4 electrolyte, and the corresponding assembled device exhibited a large energy density of 14.8 Wh kg–1 at a power density of 343.1 W kg–1. Such rational structural design and scalable fabrication are expected to pave the way toward the development of conducting polymers as cost-efficient electrode materials in portable and wearable devices especially operating in neutral aqueous electrolytes.