One-pot hydrothermal synthesis of novel 3D starfish-like δ-MnO2 nanosheets on carbon fiber paper for high-performance supercapacitors

Abstract

Novel 3D starfish-like δ-MnO₂ nanosheets with a hierarchical nanostructure supported on carbon fiber paper were synthesized through a facile hydrothermal method. These unique interconnected starfish-like nanosheets acting as a binder-free electrode exhibit a high specific capacitance (336 F g⁻¹ at a current density of 1 A g⁻¹), good rate capability (57.1% retention when the current density increases from 1 to 20 A g⁻¹), and extraordinary electrochemical cycling characteristics (125.3% retention of the initial specific capacitance after 7000 cycles at a high current density of 10 A g⁻¹). The impressive electrochemical performance of this starfish-like δ-MnO₂ electrode was mainly attributed to its distinctive microstructure and large BET surface area, which could highly shorten the transport path of the ion/electron and provide more electroactive sites for electrochemical reaction. Therefore, it can be expected that this unique starfish-like δ-MnO₂ electrode may have great promise for application in supercapacitors.