MnO2/porous carbon film/Ni electrodes with high-quality interface for high rate and performance flexible supercapacitors

In this work, MnO2/porous carbon film/Ni foil are fabricated for flexible supecapacitors (FSCs), in which the porous carbon film (PCF) serves as a buffer layer to facilitate the loading of the MnO2 and reduce the interfacial stress. The MnO2/PCF/Ni electrodes demonstrate a high-quality and stable interface. Microstructure observations show that the MnO2 film has a dense 2D structure with a hierarchically porous surface, which provides a large surface area for charge storage. The FSC based on MnO2/PCF/Ni electrode exhibits high-energy/power density, ultrahigh rate capability, wide frequency range, extraordinary flexibility, and superior cycle lifetime. Area (volumetric) specific capacitance of the MnO2/PCF/Ni electrode reaches 87 mF cm (2) (435 F cm (3)). Maximum volumetric energy (power) density of the supercapacitor reaches 38.65 mWh cm (3) (8.26 W cm (3)). Furthermore, the FSC has a very short time constant (0.3 similar to 0.5 ms) and exhibits minimal change in capacitance under dynamic bending. (C) 2016 Elsevier Ltd. All rights reserved.