Polyaniline–MnO2 coaxial nanofiber with hierarchical structure for high-performance supercapacitors

Abstract

We demonstrated the facile loading of ultrafine and loosened K-birnessite MnO₂ floccules on the surface of polyaniline (PANI) nanofibers by simply soaking the polyaniline nanofibers in a KMnO₄ aqueous solution for electrochemical energy storage applications. The as-prepared PANI–MnO₂ coaxial nanofibers with optimal composition, when applied as an electrode, exhibited a high specific capacitance (383 F g⁻¹ at 0.5 A g⁻¹) with good rate and cycling stability in 1 M Na₂SO₄ aqueous solution. Such intriguing electrochemical performance is mainly attributed to the synergistic effects of the combined pseudo-capacitive contributions from the core and shell. The present findings promoted the development of advanced electrode materials, exhibiting huge potential for supercapacitors.