Self-assembly of α-MnO2/Mn3O4 hierarchical structure on carbon cloth for aymmetric supercapacitors

Abstract

In this work, carbon cloth (CC) was employed as a substrate onto which α-MnO2 nanowires were grown hydrothermally as a secondary support structure. In NaBH4 aqueous solution, the surface of the MnO2 was reduced at room temperature to form α-MnO2/Mn3O4 hierarchical structure. At a current density of 2 A g−1, the specific capacitance of the α-MnO2/Mn3O4@CC was found to be 181 F g−1. The energy density of the asymmetric supercapacitor (ASC) assembled by α-MnO2/Mn3O4@CC and activated carbon reaches 118.3 Wh kg−1. After 4000 cycles at a current density of 1 A g−1, the 88% of the capacitance was retained demonstrating good cycle stability. The designed multi-level structure can effectively prevent the stacking and agglomeration of the nanowires, and provides high energy density and good cycle stability in ASC. These results provide a good experimental foundation for the development of advanced, wearable, and energy storage devices.