Synthesis and Electrochemical Performance of Flexible and Freestanding Graphene-Encapsulated PANi@MnO₂/ECNFs Nanoscale Architectures for Electrochemical Supercapacitors

We developeda facile method to construct flexible, freestanding three dimensional hierarchical electrodes that consist of graphene encapsulated one-dimensional conducting polyaniline (PANi)@MnO₂ coaxial nanowires grown on electrospun carbon nanofibers (denoted as G-PANi@MnO₂/ECNFs). A combination of XRD, SEM, and TEM techniques were used to characterize the structures of G‑PANi@MnO₂/ECNFs. Electrochemical measurements confirmed that such nanostructured composites possessed higher electrochemical capacitance than that of each individual component due to synergistic effects. The G-PANi@MnO₂/ECNFs electrode exhibited extremely high specific capacitance (1364.3 F/g at 0.3 A/g) and superior cycling stability (89.2% retention rate after 2000 cycles) in a 1 M Na₂SO₄ aqueous solution. The excellent electrochemical performance of such nanoscale architectured electrodes provides a new route to develop flexible, freestanding, and high-performance supercapacitors.