Trace-H₂O₂ Boosting the Reaction Kinetics of H₂SO₄ Intercalation into Graphite for the High-Oxidation Efficiency Preparation of Graphene Oxide for Na Ion Storage

Graphite sulfate (H 2 SO 4 -GICs), as a key precursor for graphene oxide (GO) synthesis, is difficult to synthesize by spontaneously forming H 2 SO 4 -GICs due to its huge diffusion resistance. Therefore, it is still a crucial challenge for improving the reaction kinetics of graphite flakes to form H 2 SO 4 -GICs. In this work, we discover that the amount of H 2 O 2 plays an important role in determining the formation of H 2 SO 4 -GICs in the intercalation process. The trace H 2 O 2 can trigger more O* during the reaction process, leading to the lattice distortion and reducing the interlayer diffusion resistance of graphite, and it was found that reducing the volume ratio of H 2 O 2 would promote the intercalation of H 2 SO 4 into graphite and form the stage-I H 2 SO 4 -GICs. Exfoliation efficiency and oxidation degree were improved after oxidation reaction. We also confirm that this method works for the exfoliation of large graphite, demonstrating the high-efficiency energy supply by adding minimal stoichiometric H 2 O 2 . The pretreated GO by trace-H 2 O 2 (PGO-100:1) exhibits a large interlayer spacing due to the complete exfoliation; after reduction as Na + ion storage anode material, RPGO-100:1 displays a high rate performance as well as outstanding kinetic behavior, indicating that the increased interlayer space of graphite resulting from the deep oxidation benefits fast migration of Na + ions toward a high capacity contribution and improved rate capability.