Nanomaterials are amazingly small materials, made up of atoms. An atom more or less in the right place can decide whether a nanomaterial is an efficient catalyst or battery material, or not. We cannot see the atoms with by eye, so we use a very powerful electron microscope to acquire strongly magnified pictures of the atoms. Looking at nice pictures is nice, but not sufficiently informative. Therefore, I work on quantitative models that allow us to precisely find out how many atoms are in the nanomaterial.