Robust Graphene-based Aerogel for Integrated 3D Asymmetric Supercapacitors with High Energy Density

Three-dimensional asymmetric supercapacitors (3D ASC) have garnered significant attention due to their high operating window, theoretical energy density, and circularity. However, the practical application of 3D electrode materials is limited by brittleness and excessive dead volume. Therefore, we propose a controlled contraction strategy that regulates the pore structure of 3D electrode materials, eliminates dead volume in the 3D skeleton structure, and enhances mechanical strength. In this study to obtain reduced graphene oxide/manganese dioxide (rGO/MnO2) and reduced graphene oxide/carbon nanotube (rGO/CNT) composite aerogels with a stable and compact structure. MnO2 and CNT as nanogaskets, preventing the self-stacking of graphene nanosheets during the shrinkage process. Additionally, the high specific capacitor nanogaskets significantly enhance the specific energy density of the rGO aerogel electrode. The prepared rGO/MnO2//rGO/CNT 3D ASC exhibits a high mass-specific capacitance of 216.15 F g-1, a high mass energy density of 74 Wh kg-1 at 3.5 A g-1, and maintains a retention rate of capacitance at 99.89 % after undergoing 10,000 cycles of charge and discharge at 5 A g-1. The versatile and integrated assembly of 3D ASC units is achieved through the utilization of the robust mechanical structure of rGO-based aerogel electrodes, employing a mortise and tenon structural design. Controlled shrinkage of reduced graphene oxide (rGO)-based hydrogel reduces the dead volume of structure, increases the load per unit of active substance and enhances the mechanical strength. The structure design of mortise and tenon electrode realizes multi-function and integrated assembly of three-dimensional asymmetric supercapacitors (3D ASCs). image