Coordination Polymers for High-Capacity Li-Ion Batteries: Metal-Dependent Solid-State Reversibility

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Organic electrode materials offer alternatives to inorganic materials for energy storage, potentially overcoming issues like structural instability.
• Understanding the mechanisms of metal-organic coordination polymers in reversible electrochemical processes is crucial for developing advanced batteries.
• Multielectron-transfer processes are vital for high-capacity energy storage systems.

Purpose of the Study:

• To elucidate the role of metal-dependent spatial proximity and binding affinity in the reversible redox processes of metal-organic coordination polymers.
• To investigate the in situ formation and function of metallic nanoparticles during electrochemical lithiation.
• To identify high-capacity organic-based electrode materials for energy storage applications.

Main Methods:

• Utilized combined 13C solid-state Nuclear Magnetic Resonance (NMR) spectroscopy, X-ray absorption spectroscopy (XAS), and transmission electron microscopy (TEM).
• Performed in situ electrochemical lithiation experiments to observe dynamic changes in the electrode materials.
• Conducted comprehensive screening of 3d-metal-organic coordination polymers.

Main Results:

• Demonstrated that metal-dependent spatial proximity and binding affinity critically influence reversible redox processes.
• Observed in situ generation of metallic nanoparticles during lithiation, forming conductive pathways that facilitate multielectron transfer.
• Identified cobalt-2,5-thiophenedicarboxylate as a high-capacity electrode material.

Conclusions:

• Metal-organic coordination polymers can achieve stable and reversible electrochemical processes through controlled metal-ligand interactions.
• The synergistic effect of in situ generated conductive nanoparticles and π-conjugated ligands enhances multielectron transfer capabilities.
• Cobalt-2,5-thiophenedicarboxylate exhibits promising performance for next-generation energy storage, delivering a stable specific capacity of ~1100 mA h g-1 after 100 cycles.