Dense Reduced Graphene Oxide Films Obtained by Pressing Create Stable and Compact Capacitive Energy Storage

Abstract It is generally believed that the re‐stacking of reduced graphene oxide (rGO) sheets limits the electrochemical energy storage. Therefore, rGO based electrodes are usually designed to be non‐compact porous and fluffy structures. However, fluffy structures could reduce the conductance, structure stability, and cycling stability of electrodes. Here, to balance the contradiction, three electrodes with different compactness were studied. Amazingly, dense rGO hydrogel films (DrGO‐HF) achieved by simply pressing filtrated rGO films, show highly stable (92 % capacitance retention after 250 000 cycles) and high‐performance compact capacitive energy storage, which can be attributed to the structural stability and electrical conductivity enhanced by the close contact between graphene sheets. This study clarifies the scientific fact that the re‐stacking of rGO sheets would not degrade the electrochemical energy storage performances, which is of great significance for the design and preparation of supercapacitor electrodes with high volumetric energy density.