Facilitated charge transport in ternary interconnected electrodes for flexible supercapacitors with excellent power characteristics

Abstract

Flexible and high performance supercapacitors are very critical in modern society. In order to develop the flexible supercapacitors with high power density, free-standing and flexible three-dimensional graphene/carbon nanotubes/MnO₂ (3DG/CNTs/MnO₂) composite electrodes with interconnected ternary 3D structures were fabricated, and the fast electron and ion transport channels were effectively constructed in the rationally designed electrodes. Consequently, the obtained 3DG/CNTs/MnO₂ composite electrodes exhibit superior specific capacitance and rate capability compared to 3DG/MnO₂ electrodes. Furthermore, the 3DG/CNTs/MnO₂ based asymmetric supercapacitor demonstrates the maximum energy and power densities of 33.71 W h kg⁻¹ and up to 22 727.3 W kg⁻¹, respectively. Moreover, the asymmetric supercapacitor exhibits excellent cycling stability with 95.3% of the specific capacitance maintained after 1000 cycle tests. Our proposed synthesis strategy to construct the novel ternary 3D structured electrodes can be efficiently applied to other high performance energy storage/conversion systems.