High Capacitive Energy Storage of Nest-Like Porous Graphene Microspheres Electrode with High Mass Loading

Nest-like porous graphene microspheres (NPGMs) are grown by using a chemical vapor deposition (CVD) method in a fluidized bed reactor from methane and basic magnesium carbonate microspheres (synthesized by a stirring-induced crystallization approach) as carbon source and template, respectively. The CVD-derived NPGMs have a few-layer structure and high electrical conductivity, as well as a three-dimensional individual macroarchitecture accompanied with well-developed pore channels and great structural integrity. As the electrode for a symmetric supercapacitor, the effect of different mass loadings for NPGMs-based electrodes on the capacitive energy-storage performance is investigated. Superior electrochemical properties with respect to gravimetric, areal, and total capacitances, rate capability, and durability are shown by the NPGMs-based symmetric supercapacitors, even at mass loadings up to 10 mg cm^-2 . Moreover, the electrochemical behavior of the NPGMs-based electrode is much superior to those of two-dimensional lamella-like graphene and commercial activated carbon.