Configurational Entropy Strategy Enhanced Structure Stability Achieves Robust Cathode for Aluminum Batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Rechargeable aluminum batteries (RABs) offer potential due to abundant aluminum resources, low cost, and high safety.
• Current limitations in RAB performance stem from poor cyclability and low reversible capacity of existing cathode materials.

Purpose of the Study:

• To introduce a high configurational entropy strategy for enhancing RAB cathode performance.
• To investigate the electrochemical properties and operational mechanism of a novel high-entropy oxide cathode.

Main Methods:

• Synthesis of a high-entropy (Fe, Mn, Ni, Zn, Mg)3O4 cathode material.
• Electrochemical testing to evaluate cycling stability, specific capacity, and ion diffusion.
• Ex situ characterizations to elucidate the operational mechanism.
• Theoretical calculations to understand the role of oxygen vacancies.

Main Results:

• The high-entropy (Fe, Mn, Ni, Zn, Mg)3O4 cathode demonstrated ultra-stable cycling (109 mAh g-1 after 3000 cycles) and high specific capacity (268 mAh g-1 at 0.5 A g-1).
• Ex situ studies revealed the mechanism involves redox processes of Fe, Mn, and Ni.
• Theoretical calculations confirmed oxygen vacancies enhance electrolyte-cathode interface kinetics.

Conclusions:

• The developed high-entropy oxide is a promising cathode material for advanced RABs.
• This work provides the first detailed mechanism and insights into high-entropy electrodes for multivalent ion batteries.