International audienceLithium ion-conducting glasses attract wide interest for electrochemical applications like efficient energy storage devices. This work presents a structural study on involved bonding units, based on X-ray photoelectron spectroscopy and infrared spectroscopy, of lithium phosphorus oxide and oxynitride amorphous thin films prepared by RF magnetron sputtering. A thorough consideration of the mid- and far-infrared spectral regions demonstrated structural changes at the phosphate units and the lithium ion environments triggered by nitrogen incorporation and post-deposition thermal treatment. It was found that films prepared by sputtering in pure nitrogen atmosphere have about 75 % of their nitrogen atoms in sites doubly coordinated with phosphorus (P–N=P), and the rest in triply coordinated sites. It was shown also that nitrogen incorporation favors the stability of lithium ions, while annealing enhances ionic conductivity of the oxynitride films

Surface layers at the cathode-electrolyte interface strongly affect the performance of the Li-ion cell. Such surface layers are found during manufacturing and operation of the battery. As water can never be fully excluded from the manufacturing chain, it will form an additional surface layer situated between cathode and electrolyte. In this contribution, we investigate the interaction between the LiCoO 2 electrode and H 2 O by a surface science approach. H 2 O was adsorbed stepwise onto a LiCoO 2 thin film, and intermediate X-ray photoelectron spectroscopy analysis was performed after every step. Adsorption results in the formation of a Li 2 O/LiOH-type reaction layer on top of the electrode and downward band bending attributed to a Li + -ion transfer out of the electrode.