LiFePO 4 has an interesting spin-polarized electronic structure showing a (3dv) 5 (3dV) 1 electron configuration of the Fe 2+ ion. In this work, we have experimentally evidenced the valence electronic structure of LiFePO 4 and of its delithiated compound FePO 4 by X-ray photoelectron spectroscopy (XPS), which allows a visualization of the occupied densities of states (DOS) in the valence band. XPS valence spectra were compared with the DOS obtained from DFT calculations by considering GGA and GGA + U approaches. Thanks to electrochemical extraction/insertion of Li + ions in LiFePO 4 /FePO 4 , it was possible to display the Fe 3d spindown electron of LiFePO 4 , which is not present in the valence spectrum of FePO 4 . We show that the study of XPS valence spectra is an efficient way to access the lithium insertion rate in Li x FePO 4 positive electrode materials for lithium-ion batteries. Besides the contribution to the Li-ion battery field, this paper is also a rare example of experimental evidence of a spin-resolved electronic structure from in-lab XPS experiments.

The behavior of confined anticancer carboplatin (CPT) molecules in a single (10, 10) boron nitride nanotube (BNNT) was studied by means of molecular dynamics simulations. Our study revealed a very large storage capacity of BNNT. Analysis of the energy profiles depending on the number of confined molecules, and on their spatial organization allowed us to quantify the ability of BNNT to vectorize CPT. Indeed, BNNT despite its small radius presented a large inner volume that favored stable encapsulation of multiple active anticancer molecules. Moreover, in our molecular dynamics simulations, the empty BNNT and the BNNT filled with CPT diffused spontaneously to the cell membrane and were able to passively enter inside lipid bilayers by a lipid-assisted mechanism. This property has been used to deliver naturally anticancer drugs to cellular targets. Using this enhanced drug delivery system, we have provided a definitive solution to the problem of drug release and have thus opened up a new way of targeting cancer cells. Indeed, regardless of the mode of action of the platinum complex towards the cell, the delivery of the drug on site should limit the side effects of the drug.

First principles calculations of the electronic structure of CeO2 nanoparticles (NPs) were performed to investigate published experimental data obtained by different spectroscopies.

The electronic structures of SnS and SnS2 have been investigated from first principles calculations to provide a full analysis of the valence and conduction bands. A good agreement with experimental X‐ray photoelectron spectroscopy (XPS), S Kβ X‐ray emission spectroscopy (XES) and X‐ray absorption spectroscopy (XAS) at S K, Sn L1 and Sn L3 edges is found and the main features of the spectra are analysed in terms of chemical bonding. In the case of XAS, we show that core‐hole effect is significant at the S K edge. The origin of the 119Sn Mössbauer parameters has been also investigated. The increase of the isomer shift from SnS2 to SnS is related to the increase of Sn 5s electron population and correlated to the decreasing intensity of the lowest energy peak of the XAS spectra at the Sn L3 edge. The values of the quadrupole splitting evaluated from the electric field gradients at the nucleus are explained from the Sn 5p electron anisotropy. Finally, the effects of interlayer interactions and intralayer local distortion are examined by considering different structural models.

Full DFT calculations were investigated to study the interactions between single wall functionalized carbon-based metallic nanotubes (CNTs) with carboplatin anticancer drugs (CPT). The geometry of the CNT-carboplatin was optimized considering different molecular configurations on inner and outer surfaces of the nanotube. Simulation results show that the most stable physisorption state for molecules is located inside the nanotube in a parallel configuration. More, we demonstrated that the molecular physisorption was reinforced as soon as the number of encapsulated carboplatin molecules increased, leading to a favored state where the nanovector is fulfilled by the drug. Moreover, all theoretical results show that the therapeutic agent is not affected when it is attached onto CNTs.

The 57Fe Mössbauer isomer shift and quadrupole splitting of LiFePO4 (LFP) and FePO4 (FP) were evaluated from density functional theory. The effects of structural optimization, Fe 3d electron correlation, and spin configuration are found to be rather small for the isomer shift but not for the quadrupole splitting. The observed decrease of the isomer shift from LFP to FP is explained from the variations of both Fe 4s and Fe 3d electrons and is related to differences in the Fe–O chemical bond properties caused by oxidation of high-spin Fe2+ into high-spin Fe3+. The values of the quadrupole splitting of the two compounds strongly increase from nonspin-polarized to spin-polarized calculations and then slightly increase by taking into account the Fe 3d electron correlation, providing a good agreement with experimental data. The observed decrease of the quadrupole splitting from LFP to FP is quantitatively correlated to the decrease of the magnitude of the highest principal value V ZZ of the electric field gradient (EFG) tensor arising from the anisotropy of Fe p-type electrons for FP and Fe 3d↓ electrons for LFP. The EFG of FP reflects the distortion of the FeO6 octahedra mainly arising from edge-sharing PO4 tetrahedra, while it is due to high-spin Fe2+ for LFP. Finally, the calculations predict that the sign of V ZZ changes from positive for LFP to negative for FP, reflecting electron depletion and accumulation, respectively, along the principal axis Z due to the rotation of the principal axis system. As a consequence, the charge–discharge cycles of LFP-based cathode for Li-ion batteries produce strong periodic variations of V ZZ through almost the overall EFG scale for iron compounds.

In the domain of Li-ion batteries, Mössbauer spectroscopy is mainly used for the characterization of electrode materials and the analysis of electrochemical reactions. Depending on the properties under investigation, different approaches are often considered, which are based on ex situ, in situ and operando measurements. The specific electrochemical cells and sample preparations used for such measurements are described in this paper. Applications to selected examples of cathode and anode materials are presented in order to show how Mössbauer spectroscopy, when associated with other techniques, provides essential information to understand the mechanisms and improves the performances of Li-ion batteries.

The encapsulation of phosphorous anti-cancer drugs is spontaneous inside boron nitride nanotubes.