Dual Protection Strategy by Constructing MXene-Coated Cu₂Se-Cu_1.8Se Heterojunction and CMK-3 Modification for...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Improving electrochemical performance of aluminum-ion batteries (AIBs) requires cathode materials with ideal kinetic behavior.
• Transition metal selenides offer high capacity and voltage but suffer from poor structural stability and reaction kinetics.
• Developing stable and efficient cathode materials is crucial for advancing rechargeable AIB technology.

Purpose of the Study:

• To fabricate advanced cathode materials for enhanced AIB performance.
• To address the challenges of low structural stability and poor reaction kinetics in AIBs.
• To investigate the potential of Cu₂Se-Cu₁.₈Se heterojunctions coated with MXene as a cathode material.

Main Methods:

• Fabrication of a Cu₂Se-Cu₁.₈Se heterojunction coated with MXene.
• Utilizing a CMK-3 modified separator for a two-fold protection mechanism.
• Electrochemical characterization to evaluate capacity, cycling stability, and reaction mechanisms.

Main Results:

• The Cu₂Se-Cu₁.₈Se@MXene composite achieved a high initial discharge capacity of 705.5 mAh g⁻¹ at 1.0 A g⁻¹.
• Excellent cycling stability was demonstrated, retaining 225.1 mAh g⁻¹ after 1500 cycles at 2.0 A g⁻¹.
• The study revealed the reaction mechanism of AlCl₄⁻ intercalation/deintercalation into the heterojunction.

Conclusions:

• The novel Cu₂Se-Cu₁.₈Se@MXene cathode material significantly improves the electrochemical performance of AIBs.
• The combined use of MXene and CMK-3 effectively mitigates active species dissolution and enhances electronic conductivity.
• This work provides a promising strategy for developing high-performance cathode materials for next-generation aluminum-ion batteries.