A Room-Temperature Chloride-Conducting Metal–Organic Crystal [Al(DMSO)6]Cl3 for Potential Solid-State Chloride-Shuttle Batteries

The growing demand for substitutes of lithium chemistries in battery leads to a surge in budding novel anion-based electrochemical energy storage, where the chloride ion batteries (CIBs) take over the role. The application of CIBs is limited by the dissolution and side reaction of chloride-based electrode materials in a liquid electrolyte. On the flipside, its solid-state electrolytes are scarcely reported due to the challenge in realizing fast Cl− conductivity. The present study reports [Al(DMSO)6]Cl3, a solid-state metal–organic material, allows chloride ion transfer. The strong Al-Cl bonds in AlCl3 are broken down after coordinating of Al3+ by ligand DMSO, and Cl− in the resulting compound is weakly bound to complexions [Al(DMSO)6]3+, which may facilitate Cl− migration. By partial replacement of Cl− with (Formula presented.), the room-temperature ionic conductivity of as-prepared electrolyte is increased by one order of magnitude from 2.172 × 10−5 S cm−1 to 2.012 × 10−4 S cm−1. When they are assembled with Ag (anode)/Ag–AgCl (cathode) electrode system, reversible electrochemical redox reactions occur on both sides, demonstrating its potential for solid-state chloride ion batteries. The strategy by weakening the bonding interaction using organic ligands between Cl− and central metallic ions may provide new ideas for developing solid chloride-ion conductors.