Interfacial Oxygen Migration Underlies Performance Limitations in High-Loading Aluminum-Ion Batteries.
Suchita Kandpal1, Samuel Agyei Baffour1, Shuo Jin1
1Department of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York, USA.
Chemsuschem
|June 1, 2026
Summary
Rechargeable aluminum batteries (RABs) show promise but are limited by anode passivation. A new chemical etching method removes the aluminum oxide layer, improving battery performance and enabling higher cathode mass loadings.
Area of Science:
- Materials Science
- Electrochemistry
- Energy Storage
Background:
- Rechargeable aluminum batteries (RABs) offer safe and cost-effective energy storage.
- Aluminum anodes in RABs suffer from passivation due to aluminum oxide (Al2O3) layer formation.
- Existing RABs exhibit lower than expected capacities due to anode passivation and cathode infiltration.
Purpose of the Study:
- Investigate the dominant degradation mechanism in RABs.
- Identify the root causes of anode passivation and capacity limitations.
- Develop a strategy to overcome interfacial chemistry challenges in RABs.
Main Methods:
- Analyzed interfacial chemistry between aluminum anode and chloroaluminate electrolytes.
- Investigated the formation and migration of oxochloroaluminate species.
- Developed and applied a single-step chemical etching strategy for aluminum anodes.
Main Results:
- Discovered that Lewis acid-base interactions promote oxochloroaluminate species formation and cathode infiltration.
- Demonstrated that these species impede ion transport in graphite cathodes, reducing accessible capacity.
- Achieved high reversibility (Coulombic efficiency > 98%) with the chemical etching strategy at high cathode mass loadings (13 mg cm-2).
Conclusions:
- The dominant degradation mechanism involves oxochloroaluminate species formation and cathode infiltration.
- Chemical etching of the native aluminum oxide layer effectively enhances RAB performance.
- The developed strategy enables high-performance RABs with improved capacity and efficiency at practical mass loadings.
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