High-performance expanded graphite from flake graphite by microwave-assisted chemical intercalation process

Herein, a facile preparation method with characteristics of energy-saving, efficient and environmentally friendly is proposed. Firstly, GICs (Graphite Intercalation Compounds) were synthesized by microwave assisted hydrothermal method using flake graphite (FG) as raw material, H2SO4, and K2S2O8 as oxidative intercalations by microwave-assisted oxidation for 5 min, and then EG was prepared from obtained GICs by microwave irradiation for 40 s under the microwave power of 800 W, and the effect of different process conditions on EG expansion volume (EV) was studied. The results show that EG with a good expansion can be rapidly prepared by microwave irradiation, and the EV value can reach 455 mL /g under the optimal conditions. In particular, the prepared EG has a high graphitization degree with less structural damage, exihibiting good industrial application prospects. The mechanism of K2S2O8 oxidation and graphite expansion under microwave irradiation was analyzed. In adition, flexible graphite foil papers prepared with the obtained EG exhibit good electrical conductivity and thermal properties. The as prepared EG material shows an efficient adsorption of hydraulic oil and vegetable oil and excellent flame retardant performance. This preparation method is green, low cost, and safe, and can be used for the efficient batch preparation of EG.