"Gene-Editing" Design Upgrades Eutectic-Polymer Electrolytes with Ultra-High Li⁺ Conductivity.

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Chemistry

Background:

• Deep eutectic polymer electrolytes (DEPEs) combine solid polymer electrolytes and deep eutectic electrolytes for enhanced performance and safety.
• Conventional DEPEs suffer from low Li+ conductivity due to strong Li+-polymer interactions.

Purpose of the Study:

• To develop a novel deep eutectic polymer electrolyte (GEPE) with tailored molecular architecture for improved Li+ conductivity.
• To address the limitations of conventional DEPEs by reducing Li+-polymer interactions.

Main Methods:

• Designing GEPEs using isophorone diisocyanate-derived segments to introduce steric hindrance and electron-withdrawing effects.
• Characterizing ionic conductivity, Li+ transference number, and cycling stability in Li||Li symmetric cells.
• Evaluating battery performance with various cathodes (NCM, LNMO, LFP) in lithium metal batteries.

Main Results:

• Achieved an ionic conductivity of 3.00 mS cm⁻¹ at 25 °C and a Li+ transference number of 0.61.
• Demonstrated over 3000 h of cycling stability in Li||Li symmetric cells with dendrite-free Li metal deposition.
• Observed excellent electrochemical performance with diverse cathodes, including nearly 100% Coulombic efficiency and long-term stability over 10,000 cycles at 5C for Li|GEPE|LiFePO4 cells.

Conclusions:

• The novel GEPE design effectively enhances Li+ conductivity and electrochemical stability.
• GEPEs represent a promising advancement for next-generation lithium metal batteries.
• The 'gene-editing' approach offers a new strategy for designing high-performance polymer electrolytes.