Co Single-Atom Catalysis for High-Efficiency LiCl/Cl₂ Conversion in Rechargeable Lithium-Chlorine Batteries

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Lithium-chlorine (Li-Cl2) batteries offer high energy density but face challenges with chlorine gas (Cl2) adsorption and lithium chloride (LiCl) conversion efficiency.
• Poor cyclability in Li-Cl2 batteries stems from weak Cl2 adsorption and low LiCl conversion, leading to active material loss.

Purpose of the Study:

• To investigate the critical role of synergistic Cl2 adsorption and LiCl reaction energy barriers in enhancing Cl2/LiCl conversion efficiency.
• To develop a novel catalyst that addresses the limitations of conventional electrode materials in Li-Cl2 secondary batteries.

Main Methods:

• Development of a cobalt (Co) single-atom site catalyst with a Co-N4 coordination environment.
• Evaluation of the catalyst's effect on the Cl2/LiCl transformation barrier and Cl2 adsorption.
• Testing the performance of the Li-Cl2@Co-NC battery under various current densities and temperatures.

Main Results:

• The Co-N4 catalyst significantly reduced the transformation barrier of LiCl to Cl2 and enhanced Cl2 adsorption.
• The developed Li-Cl2@Co-NC battery demonstrated a 0.6 V reduction in polarization voltage under high current densities.
• The battery achieved over 600 cycles at 1500 mA g-1 at room temperature and 650 cycles at 500 mA g-1 at -40 °C.

Conclusions:

• The research successfully overcame the cycle stability limitations in high-current Li-Cl2 batteries.
• The Co-N4 catalyst provides a viable strategy for developing long-cycle-life batteries with a wide operating temperature range.
• This work paves the way for advanced energy storage solutions utilizing Li-Cl2 chemistry.