Lithiation-induced shuffling of atomic stacks.

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Understanding atomic-scale structural changes in electrode materials is crucial for designing advanced rechargeable lithium-ion batteries.
• Lithium-ion intercalation induces significant structural evolution in host materials, impacting battery performance and longevity.

Purpose of the Study:

• To elucidate the atomic-scale mechanism of crystalline-crystalline phase transitions in single-crystal zinc-antimony (Zn-Sb) intermetallic nanowires during lithiation.
• To investigate the role of geometrical confinement stress and anisotropic lithium diffusion in mediating these phase transitions.

Main Methods:

• In situ transmission electron microscopy (TEM) was employed to observe the dynamic structural evolution at the atomic level.
• Analysis focused on the intermediate hexagonal (h-)LiZnSb phase and its transformation to the cubic (c-)Li2ZnSb phase.

Main Results:

• A novel atomic shuffling mechanism was identified in the h-LiZnSb phase, driven by confinement stress and anisotropic lithium diffusion.
• The formation of partial dislocations was observed during this transient structural rearrangement.
• A nearly zero-strain coherent interface was characterized between the h-LiZnSb and c-Li2ZnSb phases along specific crystallographic directions.

Conclusions:

• The study reveals a new mechanism for electrochemically driven crystalline-crystalline phase transitions in lithium-ion battery electrodes.
• Atomic-level structural and interfacial rearrangements are key to accommodating lithium intercalation and enabling high-performance electrodes.