Cavitation stripping of graphene by circulating supercritical carbon dioxide jet and its properties

Abstract

In this paper, graphene was stripped by circulating liquid phase method, supercritical carbon dioxide was selected as stripping agent, and a cavitation device was set on the pipeline to generate supercritical carbon dioxide jet cavitation to strengthen graphene stripping. Using the characteristics of small molecule intercalation and easy separation of scCO2, we succeeded in stripping graphene with fewer layers. With pressure of 10–16 MPa, temperature of 40 °C, time of 1 h, supercritical carbon dioxide circulation flow of 12 L/h, 0.47 mg/ml graphene dispersion can be obtained. Through electron microscope characterization, it can be judged that its ID/IG value was only 0.167, and the proportion of double-layer graphene reached 65%. Using the obtained dispersion to prepare flexible films, graphene films with resistivity of 0.0239 Ω /m, sensitivity of 176 and stable performance after 1000 cycles can be obtained. The advantage of this method was to avoid using expensive organic solvents such as NMP. After jet cavitation strengthening, the efficiency was higher and the conditions were milder than that of the simple supercritical carbon dioxide stripping method, which was conducive to the realization of industrial application.