REASSESSING OF THE LITHIUM INTERCALATION MECHANISM IN LAYERED NICKEL

The study of the powder diffraction diagrams of die LixNiPS3 intercala tes has been reassessed using the highly sensitive INEL curve detector . This detector used in the Debye-Scherrer geometry and with a monochr omated radiation allowed the accurate recording of the air sensitive n ickel thiophosphate intercalates powder diffraction patterns and their subsequent processings, an experiment never done before. The study sh owed that the intercalation proceeds according to a macroscopic biphas ed mechanism, which was not found in previous works. The two phases im plied are the starting phase NiPS3 and die fully reduced end-compound Li2NiPS3. For this latter material, monoclinic and hexagonal cell para meters are proposed. The study of the pristine phase's Full Width at H alf Maximum diffraction line variation during lithium intercalation sh ows that the non-intercalated grains are sensitive, through microstrai n broadening or/and size decrease, to the formation of the Li2NiPS3 in tercalate. These results answer earlier conflicting observations, in p articular about the quasi-equilibrium discharge curves.