Cooperative Anode‐Electrolyte Interface Engineering for Wide‐Temperature Aqueous Aluminum‐Ion Batteries

ABSTRACT

Aqueous aluminum‐ion batteries (AAIBs) are attractive for safe and low‐cost energy storage but are fundamentally constrained by the thermodynamic instability of metallic Al in aqueous electrolytes, which induces hydrogen evolution and interfacial corrosion, particularly at sub‐zero temperatures. We report a cooperative anode‐electrolyte interface (AEI) engineering strategy that simultaneously regulates Al ³⁺ solvation chemistry and anode surface crystallography to stabilize Al anodes in aqueous electrolytes. Introducing panthenol into a conventional Al(ClO ₄ ) ₃ electrolyte results in the formation of a hydrated eutectic system that reconstructs the hydrogen‐bond network and tailors Al ³⁺ solvation structures. This electrolyte system is inherently nonflammable and exhibits an expanded electrochemical stability window, along with an ionic conductivity of 2.17 mS cm ⁻¹ at −30°C. Meanwhile, trace alloying–directional etching (TADE) generates a nanoporous Al anode enriched with Al(200) facets that suppress proton adsorption and lower the Al nucleation barrier. The regulated solvation sheath induces an anion‐rich organic interphase, enabling stable cycling for 300 h at 30°C and −10°C, and operation at −25°C. This work establishes AEI engineering as a general strategy for wide‐temperature AAIBs.