Supercapacitors, that show high power density, fast charge/discharge capability, and long cycling life, are extensively studied as they are considered to be effective complements to lithium-ion batteries. However, low energy density of super-capacitor largely impedes many of its proposed applications. Thus, great effort has been devoted toward increasing the energy density ( E ) of supercapacitor by either enhancing the speciﬁ c capacitance ( C ) of electrode materials, or increasing the operation voltage windows ( V ), or both, since E = 1/2 CV 2 . [ 1 ] It is well known that the electrochemical storage capability depends greatly on the many aspects of electrode materials including their morphologies, compositions, sur-face properties, their intrinsic crystalline texture, and elec-trical conductivity. [ 2 ] Generally, high speciﬁ c capacitance can be achieved by increasing surface area, enhancing electrical conductivity, and inducing redox-reactions-related pseudoca-pacitance. In regard of this, numerous high-surface-area car-bonaceous materials with functionality have been developed to achieve improved performance of supercapacitor, which are mainly for high-rate capability but still low energy densi-ties due to their low double-layer capacitances.