Holey Layered Oxygen‐Rich Graphene Xerogels for High‐Performance Supercapacitors

Holey layered oxygen‐rich graphene (HLGH) xerogel material is prepared with a green pore‐making agent (potassium ferrate, K 2 FeO 4 ), whose morphology and pore structure are completely different from traditional 3D graphene xerogels. The extra oxygen‐containing functional groups existing around the in‐plane pores in HLGH xerogels can contribute more pseudocapacitance to the total capacitance. The optimal HLGH xerogels electrode material obtained a high specific capacitance of 329.5 F g −1 at 1 A g −1 , which is much larger than that of traditional graphene xerogel (GH, 169.0 F g −1 ). Finally, the symmetric supercapacitor is assembled by using the HLGH xerogels, which achieves the high energy (25.3 Wh kg −1 ) and power densities (0.9 kW kg −1 ). The specific capacitance is only reduced by 10% after 5000 cycles, showing the excellent stability. Herein, an insight for designing a high‐performance graphene carbon‐based supercapacitor is provided.