Decoding Interfacial Evolution of Aluminum Anode and Constructing Multifunctional Layers toward Ultra-Long Cycle...

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Rechargeable aluminum batteries (RABs) offer high theoretical capacity but suffer from anode instability.
• The dynamic evolution of the aluminum anode interface in ionic liquid electrolytes is a key challenge for practical application.
• Imidazolium cations (EMI+) in electrolytes are identified as primary drivers of anode degradation and instability.

Purpose of the Study:

• To understand the interfacial evolution of aluminum anodes in ionic liquid electrolytes.
• To develop a protective layer that mitigates anode degradation and enhances cycling stability in RABs.
• To resolve the long-standing interfacial issues hindering the large-scale application of RABs.

Main Methods:

• Advanced in situ characterizations were employed to investigate anode interface dynamics.
• A metal-organic framework (MOF-C) layer with selective nanochannels was engineered.
• Differential access mechanism utilized to block corrosive cations (EMI+) and facilitate anion (AlCl4-) diffusion.

Main Results:

• A transition from dendrite formation to corrosion was observed on the aluminum anode.
• The engineered MOF-C layer effectively blocked corrosive EMI+ cations while promoting AlCl4- diffusion.
• Modified Al/MOF-C anodes demonstrated exceptional cycling stability exceeding 11,000 hours in symmetric cells.
• Full cells with natural graphite cathodes retained 95% capacity over 500 cycles.

Conclusions:

• Imidazolium cations (EMI+) are the main cause of anode degradation in RABs.
• The MOF-C layer provides an effective solution for stable aluminum anodes by controlling interfacial evolution.
• This work establishes a viable strategy for developing next-generation, stable rechargeable aluminum batteries.