Liquid phase exfoliation of graphene using ammonia as an easy-to-remove additive in low-boiling organic-water co-solvent suspensions

Abstract Graphene nanosheets from suspensions are key to applications such as in printable films, battery/supercapacitor electrodes, fillers in composite materials or catalyst supports. We present a straightforward method for achieving high-concentration and long-term stable graphene suspensions by...

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Main Authors: Martin Nastran, Paul Peschek, Izabela Walendzik, Jakob Rath, Bernhard Fickl, Jasmin S. Schubert, Wolfgang Ipsmiller, Andreas Bartl, Gerd Mauschitz, Gabriel Szabo, Richard A. Wilhelm, Jochen Schmidt, Dominik Eder, Bernhard C. Bayer
Format: Article
Language:English
Published: Nature Portfolio 2025-05-01
Series:Communications Chemistry
Online Access:https://doi.org/10.1038/s42004-025-01517-y
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Summary:Abstract Graphene nanosheets from suspensions are key to applications such as in printable films, battery/supercapacitor electrodes, fillers in composite materials or catalyst supports. We present a straightforward method for achieving high-concentration and long-term stable graphene suspensions by liquid phase exfoliation (LPE) via a combination of ammonia (NH3) as an easily removable additive together with low-boiling point, benign organic-water co-solvent mixtures as suspension media. We find that the addition of small amounts of NH3 as an additive drastically improves the obtainable LPE graphene concentrations by up to 2 orders of magnitude for a wide range of organic-water co-solvent mixtures including with isopropanol, methanol, ethanol, 1-propanol, tetrahydrofuran, acetonitrile, acetone, ethylene glycol and tert-butanol. With our approach we readily reach current benchmark graphene concentration values of ~180 mg·L-1 that are normally only obtainable using hard-to-remove high-boiling-point and hazardous standard solvents like dimethylformamide and 1-methyl-2-pyrrolydone or with hard-to-remove surfactants. Notably, NH3 as an additive is highly volatile and thus, as we show, easily removable without degrading the produced high quality graphene nanosheets.
ISSN:2399-3669