Chloride‐Bridge Reshaped Electric Double Layer Enables Oriented Deposition for High‐Performance Aqueous Aluminum Ion Batteries

Abstract

ABSTRACT Aqueous aluminum‐ion batteries (AAIBs) have emerged as a promising candidate for large‐scale energy storage. However, the strong solvation of Al 3+ ions and the formation of passivating oxide layers impede interfacial charge‐transfer kinetics, resulting in progressive performance degradation during prolonged cycling. Herein, a chloride‐bridge strategy is proposed by employing trichloroethanol (TCE) as an additive that spontaneously self‐assembles at the electrolyte/electrode interface to form a chloride‐bridge‐rich molecular layer. The resulting chloride‐bridge framework reorganizes the electric double layer (EDL), accelerates interfacial charge‐transfer kinetics, and promotes uniform Al 3+ deposition with a preferred (111) crystallographic orientation. The tailored interface sustains highly reversible Al deposition/stripping for over 800 h with low polarization and enhances the FeCoPBA full‐cell lifetime from fewer than 50 cycles in the OTF electrolyte to 150 at 100 mA g −1 and 300 cycles at 200 mA g −1 . Furthermore, the PANI cathode delivers 116 mAh g −1 after 200 cycles at 100 mA g −1 and remains stable over 350 cycles at 200 mA g −1 , whereas the OTF electrolyte retains only 46 mAh g −1 after 200 cycles at the same current rate. This work establishes a chloride‐bridge‐mediated interfacial engineering strategy for accelerating interfacial charge‐transfer kinetics and enabling durable AAIBs.