Thanks to their low toxicity, chemical stability, and remarkable electrical and optical properties, carbon-based nanomaterials are finding more and more applications across electronics, energy conversion and storage, catalysis, and biomedicine. Carbon nano-onions (CNOs) are certainly no exception. First reported in 1980, CNOs are nanostructures composed of concentric shells of fullerenes, resembling cages within cages. They offer multiple attractive qualities such as a high surface area and large electrical and thermal conductivities.
