Porous asphalt/graphene composite for supercapacitors with high energy density at superior power density without added conducting materials†
The promotion of electrode active materials with higher rate capabilities and lower cost has been a long-standing challenge in the field of supercapacitors. In this work, a novel composite of asphalt with graphene oxide is developed, and it is found that the introduction of a small amount of graphene oxide such as 1 wt% could increase conductivity up to ∼400% and surface area up to ∼114%. The composite materials without the addition of any conducting material demonstrate both high capacitance and cycling stability. In addition, their rate capability is well maintained from 0.5 A g−1 to 100 A g−1 with high capacitance retention (∼88%). Furthermore, the optimized material, which is made mainly from the cheap waste material asphalt, demonstrates an excellent energy density (22.0 Wh kg−1) at an ultra-high power density (55.4 kW kg−1), which indicates its promising potential for industrial applications in green energy.