▎ 摘　　要

Mass production of high quality graphene platelets has attracted considerable interest for potential applications in various fields. Nevertheless, in literature, the graphite oxide (GO)-derived graphene is always lacking high crystallinity and hierarchical porosity. Herein, we report a new molten sodium-induced graphitization for mass-fabricating highly crystalline and porous graphene sheets. The 3D graphene hydrogels (GHs) obtained from GO by the hydrothermal self-assembly are directly annealed in molten sodium at 800 degrees C. As a result, the D band intensity in Raman spectroscopy is reduced significantly, while 2D band intensity is increased prominently, which is a typical characteristic of highly crystalline graphene. More importantly, the resulting Na-GFs-800 sample exhibits increased surface area and narrow mesopore size distribution (similar to 3.6 nm). The excellent supercapacitive performance of Na-GFs-800 has been demonstrated in an organic symmetric system. Meanwhile, the possible interaction mechanism between molten sodium and GHs has been proposed in the text.