The systematic co-occurrence of B, Co and a minor concentration of O, as depicted in Fig. ). Owing the low local concentration and its unsuited shape of the ionization edge in conjunction with the challenging sample geometry, any P distribution could not be derived with the EELS technique (see experimental section). However, the homogeneous incorporation of P is proven by STEM X-ray spectroscopy (Fig. ) and XPS (Fig. K, Fig. ).