Constructed Uninterrupted Charge-Transfer Pathways in Three-Dimensional Micro/Nanointerconnected Carbon-Based Electrodes for High Energy-Density Ultralight Flexible Supercapacitors

Abstract

A type of freestanding three-dimensional (3D) micro/nanointerconnected structure, with a conjunction of microsized 3D graphene networks, nanosized 3D carbon nanofiber (CNF) forests, and consequently loaded MnO<sub>2</sub> nanosheets, has been designed as the electrodes of an ultralight flexible supercapacitor. The resulting 3D graphene/CNFs/MnO<sub>2</sub> composite networks exhibit remarkable flexibility and highly mechanical properties due to good and intimate contacts among them, without current collectors and binders. Simultaneously, this designed 3D micro/nanointerconnected structure can provide an uninterrupted double charges freeway network for both electron and electrolyte ion to minimize electron accumulation and ion-diffusing resistance, leading to an excellent electrochemical performance. The ultrahigh specific capacitance of 946 F/g from cyclic voltammetry (CV) (or 920 F/g from galvanostatic charging/discharging (GCD)) were obtained, which is superior to that of the present electrode materials based on 3D graphene/MnO<sub>2</sub> hybrid structure (482 F/g). Furthermore, we have also investigated the superior electrochemical performances of an asymmetric supercapacitor device (weight of less than 12 mg/cm<sup>2</sup> and thickness of ∼0.8 mm), showing a total capacitance of 0.33 F/cm<sup>2</sup> at a window voltage of 1.8 V and a maximum energy density of 53.4 W h/kg for driving a digital clock for 42 min. These inspiring performances would make our designed supercapacitors become one of the most promising candidates for the future flexible and lightweight energy storage systems

    Similar works

    Full text

    thumbnail-image

    Available Versions