Researchers at Montana State have successfully strengthened solid-state separators.

Status: Available for Licensing and/or Collaboration

Background:

Solid-state batteries are the next generation of energy storage, offering superior energy density and safety over liquid systems. Garnet-structured oxides like Li₇La₃Zr₂O₁₂ (LLZO) are the industry standard for solid electrolyte separators due to their stability with lithium metal. However, commercial adoption is restricted by critical mechanical limitations:

  • Exhibiting inherent brittleness, the ceramic matrix is fragile, making thin separator layers challenging to handle and process during large-scale manufacturing.
  • Displaying low fracture toughness, the material is susceptible to localized microcracking under operational stresses.
  • Allowing dendrite propagation, these microcracks enable lithium penetration, leading to short-circuiting and cell failure.

Solution:

By controlling material changes, this invention strengthens solid-state separators. When a crack forms, the improved LLZO shifts its structure to absorb energy and close the crack—a toughening mechanism demonstrated in LLZO ceramics. The design offers three main benefits:

  • Enhancing durability by making the ceramic tougher and more resistant to breakage during handling and manufacturing.
  • Blocking dendrite growth by preventing tiny cracks from forming pathways for lithium metal, thereby reducing the risk of short circuits.
  • Improving battery safety by enhancing long-term reliability and operational lifespan.

Performance:

Tests of the improved LLZO material demonstrated a 250% increase in toughness compared to conventional garnet electrolytes. This strength is expected to raise critical current density, enabling faster charging and better safety in solid-state lithium batteries (See Figure 1 for SEM evidence of crack arrest.).

SEM Evidence of Crack Arrest in LLZO Electrolytes

Figure 1. SEM Evidence of Crack Arrest in LLZO Electrolytes.

 

SEM images of micro-indented LLZO. (A, left) Conventional LLZO showing a long, propagating crack (yellow arrow). (B, right) DSSE LLZO showing significantly shorter cracks, indicating crack arrest and enhanced toughness. Scale bars: 2 μm.

 

 

Applications:

  • Enabling advanced battery technologies
  • Providing solid-state separators for lithium-based systems
  • Supporting aerospace and extreme environment applications

Collaboration Opportunities:

  •  Patent and Know-How available for licensing
  • Collaborate on research projects for further development and testing
  • Access to specialized equipment and expertise for material characterization

Supporting Publications:

Lessmeier, Matt and Heywood, Stephen and Driscoll, David and Sofie, Stephen, Transformation Toughening of Garnet Structured LLZO Solid Electrolyte. Available at: https://ssrn.com/abstract=6065886

Contact:

Casey Wegner, Senior Technology Manager
Montana State University Technology Transfer Office
Email: casey.wegner@montana.edu
Phone: (406) 994-7764