A spacer-modified nano graphene platelet electrode, comprising: (a) multiple nano graphene platelets or sheets having an average thickness smaller than 10 nm; and (b) discrete, non-metallic nano-scaled particles that are disposed between two graphene platelets or sheets to serve as a spacer. In such a spacer-modified graphene electrode, large amounts of electrolyte-accessible pores are formed, enabling the formation of large amounts of electric double layer charges in a supercapacitor, which exhibits an exceptionally high specific capacitance.