Atomic-Level Interfacial Regulation Enables Efficient Chlorine Redox Chemistry in Rechargeable H₂─Cl₂ Batteries

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Hydrogen-chlorine (H2-Cl2) batteries offer high power but suffer from poor chlorine (Cl2) confinement and slow Cl2/Cl- redox kinetics.
• Inefficient Cl2 management limits the practical application and stability of these energy storage systems.

Purpose of the Study:

• To develop a material that enhances Cl2 confinement and accelerates Cl2/Cl- redox reactions in H2-Cl2 batteries.
• To investigate the role of atomically dispersed copper sites within a porphyrin framework for improved electrochemical performance.

Main Methods:

• Fabrication of a hydrogen-bonded porphyrin framework with atomically dispersed copper sites (SACu-GTUB5).
• Utilized synergistic physical confinement and chemical adsorption for Cl2 storage.
• Employed spectroscopic analyses and density functional theory (DFT) calculations to study reaction mechanisms.

Main Results:

• The SACu-GTUB5 framework demonstrated efficient Cl2 storage, suppressing Cl2 escape and improving Coulombic efficiency.
• H2-Cl2 batteries using SACu-GTUB5 showed stable operation from -40°C to 60°C.
• Achieved a high areal discharge capacity of 2.55 mAh cm-2 over 300 cycles, with Cu-N4 sites lowering energy barriers for Cl2 reduction.

Conclusions:

• Atomically dispersed Cu-N4 sites within the porphyrin framework effectively regulate interfacial Cl2 redox chemistry.
• This atomic-level interfacial regulation strategy significantly enhances the performance and stability of H2-Cl2 batteries.
• The developed material offers a promising approach for advanced electrochemical energy storage solutions.