Titanium Sulfides as Intercalation-Type Cathode Materials for Rechargeable Aluminum Batteries

We report the electrochemical intercalation–extraction of aluminum (Al) in the layered TiS 2 and spinel-based cubic Cu 0.31 Ti 2 S 4 as the potential cathode materials for rechargeable Al-ion batteries. The electrochemical characterizations demonstrate the feasibility of reversible Al intercalation in both titanium sulfides with layered TiS 2 showing better properties. The crystallographic study sheds light on the possible Al intercalation sites in the titanium sulfides, while the results from galvanostatic intermittent titration indicate that the low Al 3+ diffusion coefficients in the sulfide crystal structures are the primary obstacle to facile Al intercalation–extraction.