Layered TiS₂ Positive Electrode for Mg Batteries

Magnesium batteries are a good candidate for high energy storage systems, but the limited discovery of functional positive electrode materials beyond the seminal Chevrel phase (Mo 6 S 8 ) has slowed their development. Herein, we report on layered TiS 2 as a promising positive electrode intercalation material, providing 115 mAh g –1 stabilized capacity in a Mg full cell. Reversible Mg 2+ intercalation into the structure is proven by elemental analysis combined with X-ray diffraction studies that elucidate the phase behavior upon cycling. The voltage profiles reveal distinct Mg 2+ cation ordering, unlike the solid solution behavior exhibited by Li + . Our findings not only point to the important role of “soft” lattices to facilitate divalent solid-state cation mobility but also now provide an alternative sulfide to serve as a platform for the fundamental understanding of Mg 2+ intercalation in lattices.