Graphene oxide (GO) membranes with 2D interlaminar channels have triggered intensive interest as ion conductors. Incorporating abundant ion-conducting sites into GO interlayers is recognized as an effective strategy to facilitate ion conduction. Herein, we designed supramolecular compounds, para-sulphonato-calix[n]arenes (p-SC[n]As), as versatile intercalators to acquire highly conductive and robust GO membranes. The SC[n]A with ultrahigh ionic exchange capacity (IECw, 5.37 mmol g-1) imparts sufficient proton donors, and its rigid framework imparts strong support of adjacent nanosheets. We designed three kinds of SC[n]As with the same IECw but different sizes as intercalators, endowing the GO/SC[n]A membranes with increasing ion concentration and d-spacing in the order of GO/SCA < GO/SCA < GO/SCA. Therefore, the interlayers of GO/SCA membranes afforded higher density of proton donors and could accommodate more water molecules to construct more continuous H-bond networks for proton transfer. Accordingly, the proton conductivities exhibited the same increasing trend, up to 327.0 mS cm-1 of GO/SCA-30% at 80 °C, 100% RH, which was 2.80 times higher than that of the GO membrane. Moreover, the GO/SC[n]A membranes remained stable in wet state, along with a 66% elevation in mechanical performance compared to the GO membrane.
ASJC Scopus subject areas
- Materials Science(all)