LAUSR

Abstract Considering the growing requirement for high-performance energy storage devices, active electrode materials with high volumetric performance are urgently needed, but only few reports devote to the preparation of reduced graphene oxide (rGO) with high gravimetric specific capacitance (Cg) and volumetric specific capacitance (Cv). Here, the thermally treated dense rGO films are further treated with concentrated sulfuric acid to achieve the high Cg, Cv and cycling stability. The optimal film possesses high density of about 2.04 g cm−3 and exhibits the maximal Cg and Cv of about 242.3 F g−1 and 494.3 F cm−3 in 1.0 mol L−1 H2SO4 electrolyte based on the two-electrode testing system. Furthermore, the optimal film shows excellent cycling stability in 1.0 mol L−1 H2SO4 (90.2% capacitance retention after 10000 cycles) and excellent rate capability. It is believed that this strategy can be developed as an effective process to prepare rGO-based materials with high capacitive performance for compact energy storage device.