Nastran Martin, Peschek Paul, Walendzik Izabela, Rath Jakob, Fickl Bernhard, Schubert Jasmin S, Ipsmiller Wolfgang, Bartl Andreas, Mauschitz Gerd, Szabo Gabriel, Wilhelm Richard A, Schmidt Jochen, Eder Dominik, Bayer Bernhard C
Technische Universität Wien (TU Wien), Institute of Materials Chemistry, Getreidemarkt 9/165, Vienna, Austria.
Wrocław University of Science and Technology, Department of Process Engineering and Technology of Polymer and Carbon Materials, Gdańska 7/9, Wrocław, Poland.
Commun Chem. 2025 May 23;8(1):161. doi: 10.1038/s42004-025-01517-y.
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 (NH) 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 NH 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 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, NH as an additive is highly volatile and thus, as we show, easily removable without degrading the produced high quality graphene nanosheets.
来自悬浮液的石墨烯纳米片对于诸如可印刷薄膜、电池/超级电容器电极、复合材料中的填料或催化剂载体等应用至关重要。我们提出了一种直接的方法，通过液相剥离（LPE），将氨（NH₃）作为易于去除的添加剂，与低沸点、良性的有机-水共溶剂混合物作为悬浮介质相结合，来实现高浓度和长期稳定的石墨烯悬浮液。我们发现，对于包括异丙醇、甲醇、乙醇、1-丙醇、四氢呋喃、乙腈、丙酮、乙二醇和叔丁醇在内的多种有机-水共溶剂混合物，添加少量NH₃作为添加剂可将可获得的LPE石墨烯浓度大幅提高多达2个数量级。采用我们的方法，我们很容易达到目前约180 mg·L⁻¹的基准石墨烯浓度值，而这些值通常只能使用难以去除的高沸点和危险标准溶剂（如二甲基甲酰胺和1-甲基-2-吡咯烷酮）或难以去除的表面活性剂才能获得。值得注意的是，NH₃作为添加剂具有高挥发性，因此，正如我们所展示的，它很容易去除，而不会降解所制备的高质量石墨烯纳米片。
