Improving Ionic Conformality Across Polymer Electrolyte|Electrode Interfaces

Area of Science:

• Materials Science
• Electrochemistry
• Chemical Engineering

Background:

• Maintaining uniform ionic transport at electrode-electrolyte interfaces, known as ionic conformality, is a critical challenge in polymer electrolyte (PE)-based solid-state batteries.
• In multiphase PEs, ion-conductive domains can rearrange or deplete at interfaces, disrupting ion transport pathways and leading to interfacial instability and capacity fade, especially in high-voltage lithium-metal batteries.

Purpose of the Study:

• To demonstrate an electrolyte design strategy that minimizes interfacial heterogeneities for improved ionic conformality.
• To enhance cycling stability and performance of solid-state batteries at high voltages.

Main Methods:

• Compositional adjustments in the electrolyte to minimize interfacial heterogeneities.
• Spatially resolved structural and chemical X-ray techniques for interface characterization.
• NMR diffusometry to elucidate ion transport dynamics.

Main Results:

• The proposed electrolyte design approach successfully improved ionic conformality at electrode interfaces.
• Enhanced cycling stability was observed in Li||LiNi0.8Co0.1Mn0.1O2 (NMC811) coin and pouch cells cycled at high voltages.

Conclusions:

• Minimizing interfacial heterogeneities through compositional control is an effective strategy to achieve ionic conformality in multiphase PEs.
• The findings provide insights into interfacial behaviors and inform future strategies for developing stable solid-state battery interfaces.