Effect of deformation temperature on the coupled corrosion – Discharge mechanisms of aluminum-air battery anodes

Abstract

This study investigates the interplay between parasitic corrosion and transport-limiting passivation in alkaline aluminum–air batteries using aluminum–magnesium–bismuth–indium anodes processed across a deformation-temperature gradient (cryogenic→ room temperature → dynamic recovery → near-recrystallization). A temperature-driven microstructure–film–performance coupling is identified. As deformation temperature increases, the fraction of dynamically recrystallized grains rises (∼0.7 % to ∼7.1 %), dislocation density decreases (∼2.21 ×10 ¹⁴ to ∼1.66 ×10 ¹⁴·m⁻²), and texture shifts from beta-fiber to alpha-fiber/copper. These changes alter interfacial film kinetics: from activation-controlled dissolution with sparse nuclei (cryogenic) to semi-permeable Al(OH)₃/Al₂O₃ films (room-temperature/recovery), and ultimately to dense, continuous discharge product layers (near-recrystallization). This shift reduces corrosion depth (∼586 µm to ∼333 µm), as semi-permeable films suppress localized corrosion, while dense films hinder ion exchange, redirect hydroxide ions along grain boundaries, and promote boundary-guided cracking and exfoliation corrosion (∼613 µm). Electrochemical data show that charge-transfer resistance decreases and then increases with temperature, while film/diffusion resistance increases monotonically, indicating densification and transport limitation. The room-temperature/recovery window minimizes the combined penalty of charge-transfer and diffusion polarizations, suppressing self-corrosion/intergranular corrosion, and enabling higher, more stable voltages and peak energy output (∼2618 mWh·g⁻¹, ∼86.56 % utilization). These results highlight deformation temperature as a key factor in tuning microstructure-controlled film growth, which governs corrosion pathways and discharge performance.