An Adhesive Adaptation Layer Mitigates the Interfacial Instabilities of Rigid Polymer Electrolyte

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Solid polymer electrolytes (SPEs) are key for safer, high-energy solid-state lithium metal batteries (SSLMBs).
• Conventional wisdom suggests rigid SPEs improve lithium deposition control, but they can fail due to anode volume changes causing delamination.

Purpose of the Study:

• To investigate a novel failure mechanism in rigid SPEs related to volumetric changes of the lithium metal anode.
• To develop and evaluate a hierarchical SPE (H-SPE) with an adhesive adaptation layer (AAL) to overcome delamination and improve interfacial stability.

Main Methods:

• Fabrication of a hierarchical SPE with an integrated AAL between the lithium metal anode and the rigid SPE.
• Structural characterization using Cryo-TEM and SEM to analyze lithium deposition morphology.
• Electrochemical performance testing of the H-SPE in SSLMBs with high-loading NMC622 cathodes.

Main Results:

• The AAL effectively mitigates delamination by providing adhesion and accommodating anode volume changes.
• Hierarchical SPEs promote uniform, dense, and whisker-free lithium deposition, unlike rigid SPEs.
• Enhanced interfacial stability leads to an inorganic-enriched SEI layer and improved long-term cycling.

Conclusions:

• The hierarchical SPE design with an AAL successfully addresses the delamination failure mode in SSLMBs.
• This approach enables stable cycling of lithium metal anodes against high-loading cathodes.
• The developed H-SPE demonstrates significant potential for advancing high-performance and safe solid-state batteries.