Significant Strain Dissipation via Stiff-Tough Solid Electrolyte Interphase Design for Highly Stable Alloying Anodes.

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Alloying anodes in lithium-ion batteries (LIBs) suffer from pulverization, limiting their practical application.
• Developing stable solid electrolyte interphase (SEI) layers is crucial for enhancing anode durability and battery performance.

Purpose of the Study:

• To design and evaluate a dual-phase SEI incorporating aluminum (Al) nanoparticles within a lithium phosphorus oxynitride (LiPON) matrix.
• To investigate the mechanical properties (stiffness and toughness) and electrochemical performance of the novel Al/LiPON dual-phase SEI.

Main Methods:

• Fabrication of a dual-phase SEI by dispersing Al nanoparticles within a LiPON matrix.
• Mechanical testing to quantify fracture toughness and stiffness compared to single-phase LiPON.
• Electrochemical cycling tests on aluminum and silicon anodes in dual-ion and conventional LIBs.

Main Results:

• The Al/LiPON dual-phase SEI exhibited a 317.8% increase in fracture toughness while maintaining stiffness.
• Application on Al anodes resulted in a 450% enhancement in cycling stability for lithium storage.
• Improved cycling stability was also observed for silicon anodes, demonstrating broad applicability.
• Homogeneous Li-Al alloying was achieved even with high mass loading cathodes.

Conclusions:

• The dual-phase SEI design effectively integrates stiffness and toughness, addressing the pulverization issue of alloying anodes.
• This approach enhances structural stability and rate capability, paving the way for more robust LIBs.
• The SEI design also optimizes Li-ion diffusion kinetics through interface electronic structure modification.