Preparation of novel morning glory structure γ-MnO2/carbon nanofiber composite materials with the electrospinning method and their high electrochemical performance

A novel γ-MnO2/carbon nanofiber composite electrode material with a morning glory structure was prepared for the first time by electrospinning a mixture solution of Mn(CH3COO)2 salt and polyacrylonitrile and subsequently treating it with NH3 atmosphere. The resultant materials were applied in supercapacitors, exhibiting a high voltage of 2 V and high energy density of 15.7 W h kg-1 at the current density of 0.5 A g-1 in 1 M Na2SO4 solution. In this study, precisely controlling the concentration and time of the reaction resulted in the novel morning glory structure. And the morning glory structure at the surface of the carbon nanofibers increased the specific surface area and shortened the diffusion path for charge transport, increasing the Na+/H+ ion intercalation capacity, accounting for the high voltage and energy density of the present supercapacitors. These results demonstrated that this new-type of carbon nanofiber with morning glory structure electrode material is potentially superior in obtaining a high voltage for electrode materials and supercapacitors. We hope that these novel materials can expand to different applications in the energy or catalytic field.