Surface dynamic of copper nitroprusside as a cathode material: observation by XPS and SEM

Nowadays, rechargeable Li-ion batteries play an important role in portable consumer devices. The formation of surface films on electrodes in contact with non-aqueous electrolytes in lithium-ion batteries has a deep impact on battery performance. A basic understanding of such films is necessary for the improvement of power sources. The surface chemistry and morphology of a cathode material, copper nitroprusside, have here been evaluated by X-ray Photoelectron Spectroscopy (XPS) and Scanning Electron Microscopy (SEM), and placed in relation to the performance of the electrodes. Interface formation between the cathode and carbonate-based electrolytes has been followed and characterised. The variables have been: number of charge/discharge cycles and air contact. The species precipitating on the surface of the cathodes at ambient temperature have been determined to comprise a mixture of organic and inorganic compounds: LiF, LixPFy, LixPOyFz, inorganic and organic carbonates. Moreover a problematic due to UHV and X-ray exposure has been followed.