Polypyrrole Shell@3D-Ni Metal Core Structured Electrodes for High-Performance Supercapacitors

Three-dimensional (3D) nanometal films serving as current collectors have attracted much interest recently owing to their promising application in high-performance supercapacitors. In the process of the electrochemical reaction, the 3D structure can provide a short diffusion path for fast ion transport, and the highly conductive nanometal may serve as a backbone for facile electron transfer. In this work, a novel polypyrrole (PPy) shell@3D-Ni-core composite is developed to enhance the electrochemical performance of conventional PPy. With the introduction of a Ni metal core, the as-prepared material exhibits a high specific capacitance (726Fg(-1) at a charge/discharge rate of 1Ag(-1)), good rate capability (a decay of 33% in C-sp with charge/discharge rates increasing from 1 to 20Ag(-1)), and high cycle stability (only a small decrease of 4.2% in C-sp after 1000cycles at a scan rate of 100mVs(-1)). Furthermore, an aqueous symmetric supercapacitor device is fabricated by using the as-prepared composite as electrodes; the device demonstrates a high energy density (approximate to 21.2Whkg(-1)) and superior long-term cycle ability (only 4.4% and 18.6% loss in C-sp after 2000 and 5000cycles, respectively).