Further, a symmetric supercapacitor electrode was assemble using HEBLC-3 in 6.0 M KOH solution, which exhibited the specific energy density 6.3 Wh Kg -1 at the power density of 102.0 W Kg -1 , and exhibited the capacitance retention over 90% after 3000 cycles. In 1 M Na2SO4 electrolyte solution, the HEBLC-3 electrode displayed the maximum energy density over 20