Quantification of Buckminsterfullerene (C-60) in non-graphitizing carbon and a microstructural comparison of graphitizing and non-graphitizing carbon via Small Angle Neutron Scattering

In this article we present the first experimental evidence confirming a global presence of Buckmin-sterfullerene (C-60) in non-graphitizing polymeric carbon, along with its volume fraction calculations. Partially stacked carbon fragments featuring weak or strong curvatures constitute the structural units in non-graphitizing carbons. It has been proposed that a certain fraction of completely closed spherical fullerenes, such as C-60, is also present in these materials. Strongly curved structures are not expected to exist in graphitizing carbons. We report on a Small Angle Neutron Scattering (SANS) investigation conducted at the Institut Laue-Langevin, Grenoble, France, that enables us to (i) quantify C-60 in a non-graphitizing carbon, (ii) investigate the evolution patterns of graphitizing and non-graphitizing carbons, and (iii) perform a detailed SANS analysis of pure crystalline C-60 in dry powder form. We also revisit the formation patterns of slightly larger structures (3-5 nm) such as graphitic crystallites and voids in both classes of polymeric carbon. These results provide a strong evidence in support of the fullerene-like microstructural models of non-graphitizing carbon, adding that the curved structural units are not just "fullerene-like", but also spherical fullerenes, C-60 in particular. (C) 2021 Elsevier Ltd. All rights reserved.