Soft X ray Emission Spectroscopy of Phosphorus Compounds for Energy Conversion and Storage

Phosphorus P is a ubiquitous component of materials for energy conversion and storage. Despite the effectiveness of soft X ray emission spectroscopy XES to characterize these complex materials, XES studies of P containing compounds are still largely missing. In this investigation, the electronic structure and XES signatures from the P L2,3 edge are probed for nine solid state P containing compounds characterized by various oxidation states and chemical environments GaP 3 amp; 8722; , InP 3 amp; 8722; , red P 0 , H3P 3 O3, Na2H2P2 4 O6, H3P 5 O4, KH2P 5 O4, Na2HP 5 O4, and InP 5 O4. The XES spectrum of each material exhibits distinct spectral fingerprints, which provide a robust basis for the speciation of complex P containing samples. Density functional theory calculations shed light on the electronic structure of selected materials and particularly on the effect of phosphorus oxygen hybridization. This study provides a comprehensive understanding of P L2,3 XES spectral fingerprints across a wide range of oxidation states and chemical environments. These data sets and insights pave the way for dedicated future work, such as in situ and operando investigations of P containing compounds in energy related applications, where speciation of P compounds is needed