Facile synthesis of multi-layer graphene-like graphitic structure using commercial candle as the solid-state carbon source for electrochemical supercapacitors

In this study, we report the synthesis of multi-layer graphene-like graphitic structure (MGGS) using commercial candle as the solid-state carbon sources, without use of any gaseous carriers and gaseous carbon sources. The MGGS layers were directly synthesized onto the porous three-dimensional Ni foam via an easy annealing route, the obtained MGGS/Ni foam electrodes were applied to electrochemical supercapacitors. The morphologies and nanostructures of MGGS layers were examined by scanning electron microscopy, Raman spectroscopy, X-ray diffraction, and transmission electron microscope. Electrochemical properties were tested by cyclic voltammetry and galvanostatic charge/discharge cycles. Capacitive performance illustrated that the MGGS synthesized by the commercial candle demonstrated the outstanding behaviors of electrical double layer capacitors (EDLCs) in the specific capacitance, rate capability, and cycling stability. Our work might provide a way for economical and convenient graphene growth of EDLCs and graphene-based applications. In particular, substituting the commonly used explosive hydrocarbon gaseous carbon sources with candle as the solid-state carbon source brings a great benefit of feasible operation for safety consideration.