Lattice pinning in MoO₃ via coherent interface with stabilized Li⁺ intercalation

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Solid-state lithium-based batteries suffer from electrode degradation due to large volume changes during ion intercalation/deintercalation.
• Layered orthorhombic molybdenum trioxide (α-MoO₃) exhibits significant lattice expansion along the b-axis, causing irreversible structural damage and limiting battery cycle life.

Purpose of the Study:

• To develop a strategy to mitigate structural degradation in α-MoO₃ electrodes for improved solid-state battery performance.
• To investigate the effectiveness of a lattice pinning approach using heterostructures to stabilize α-MoO₃ during electrochemical cycling.

Main Methods:

• Constructing a coherent interface between α-MoO₃ and η-Mo₄O₁₁ with an epitaxial intergrowth structure.
• Utilizing the minimal lattice change of η-Mo₄O₁₁ as pin centers to suppress α-MoO₃ lattice expansion.
• Characterizing the structural stability and electrochemical performance of the designed heterostructure.

Main Results:

• The α-MoO₃/η-Mo₄O₁₁ heterostructure significantly reduced lattice expansion along the b-direction from ~16% to 2%.
• The intergrown heterostructure demonstrated robust structural stability, retaining approximately 81% capacity after 3000 cycles at 2 A g^-1.
• A highly durable and flexible all-solid-state thin-film lithium microbattery was successfully fabricated using the stabilized electrode.

Conclusions:

• The lattice pinning strategy effectively suppresses structural degradation in α-MoO₃, enhancing its suitability as an electrode material.
• Epitaxial stabilization and pinning effects in heterostructures offer a promising route for developing highly stable electrode materials for advanced batteries.
• This research provides fundamental insights into the structural evolution of α-MoO₃ and presents a viable approach for next-generation solid-state batteries.