A hybrid supercapacitor constructed by graphene wrapped ordered meso-porous Si based electrode

Abstract

With merit of nano size, meso-porous structure and graphene coating, a nonstoichiometric silicon oxides, SiOx, composited material was fabricated into a newly developed lithium ion supercapacitor as negative electrode in this study. After characterization of this SiOx based material through XRD, XPS, SEM, EDS, TEM, TG and nitrogen adsorption/desorption isotherm, it was coupled with porous active carbon, which acted as positive electrode, to construct a lithium ion hybrid supercapacitor. The hybrid device then exhibited a high stable capacity of 880 mA h g−1 at the 200 mA g−1 of applied current density. A reversible specific capacity of 328 mA h g−1 is observed after 6000 charge and discharge cycles under 5 A g−1. Furthermore, quite a low, about 4.2 μA, leakage current is also revealed.