Graphite sulfate (H2SO4-GICs),
as a key precursor
for graphene oxide (GO) synthesis, is difficult to synthesize by spontaneously
forming H2SO4-GICs due to its huge diffusion
resistance. Therefore, it is still a crucial challenge for improving
the reaction kinetics of graphite flakes to form H2SO4-GICs. In this work, we discover that the amount of H2O2 plays an important role in determining the formation
of H2SO4-GICs in the intercalation process.
The trace H2O2 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 H2O2 would promote
the intercalation of H2SO4 into graphite and
form the stage-I H2SO4-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 H2O2. The pretreated GO by trace-H2O2 (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.