Achieving Both High Power and Energy Density in Electrochemical Supercapacitors with Nanoporous Graphene Materials

Supercapacitors, based on the fast ion transportation, are specialized to provide high power, long stability, and efficient energy storage with highly porous electrode materials. However, their low energy density and specific capacitance prevent them from many applications that require long duration. Using a scalable nanoporous graphene synthesis method involving a simple annealing process in hydrogen, here we show graphene supercapacitors capable of achieving a high energy density comparable to what Li-ion batteries can offer, but a much higher power density. Ultra-high specific gravimetric and volumetric capacitances are achieved with highly porous graphene electrodes. Moreover, the supercapacitors assembled with graphene electrodes show excellent stability. Our results demonstrate that by synthesizing graphene materials with an ideal pore size, uniformity, and good ion accessibility, the performance of supercapacitors can be revolutionized.