Graphitization of graphene oxide films under pressure

Lightweight, flexible graphite foils that are chemically inert, high-temperature resistant, and highly electrically and thermally conductive can be used as component materials in numerous applications. Graphenic foils can be prepared by thermally transforming graphene oxide films. For this transformation, it is desirable to maintain a densely packed film structure at high heating rates as well as to lower the graphitizing temperatures. In this work, we discuss the pressure-assisted thermal decomposition of graphene oxide films by hot pressing at different temperatures (i.e., 300 degrees C, 1000 degrees C, or 2000 degrees C). The films pressed at 1000 degrees C or 2000 degrees C were subsequently heated at 2750 degrees C to achieve a higher degree of graphitization. The combination of heating and pressing promotes the simultaneous thermal decomposition and graphitic transformation of G-O films. Films pressed at 2000 degrees C as well as films further graphitized at 2750 degrees C show high chemical purity, uniformity, and retain their flexibility. For films pressed at 2000 degrees C and then further heated at 2750 degrees C, the mechanical performances outperform the reported values of the graphite foils prepared by calendering exfoliated graphite flakes; the electrical conductivity is similar to 3.1 x 10(5) S/m and the in-plane thermal conductivity is similar to 1.2 x 10(3) W/(m.K). (c) 2018 Elsevier Ltd. All rights reserved.