Polyrotaxane-Assembled Semi-Interpenetrating Polymer Electrolytes Enabling High-Voltage Lithium Metal Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Chemistry

Background:

• Polyether solid polymer electrolytes face challenges like low conductivity, poor oxidative stability, and dendrite growth, limiting their use in high-energy lithium batteries.
• Developing stable and efficient electrolytes is crucial for advancing next-generation lithium battery technology.

Purpose of the Study:

• To develop a novel polyrotaxane-assembled supramolecular semi-interpenetrating network electrolyte (SSNE).
• To address the limitations of conventional polyether electrolytes by enhancing ionic conductivity, oxidative stability, and dendrite suppression.
• To enable high-voltage lithium metal batteries with improved safety and energy density.

Main Methods:

• Synthesized SSNE via in situ polymerization of polyrotaxane with crosslinked polydioxolane (PDOL).
• Incorporated hierarchical ion-conduction pathways, Lewis acid sites, and spatial confinement within the polyrotaxane framework.
• Utilized host-guest interactions to decouple Li+ ion transport from anion migration.

Main Results:

• Achieved high room-temperature ionic conductivity (0.18 mS cm⁻¹).
• Demonstrated a high Li+ transference number (> 0.73).
• Extended the electrochemical window to over 4.9 V with stabilized electrode-electrolyte interphase.
• Exhibited 81.4% capacity retention after 200 cycles in a full cell prototype.
• A 1.2 Ah pouch cell operated reliably for 190 cycles at room temperature.

Conclusions:

• The SSNE architecture effectively decouples ion and anion transport, enhancing performance.
• The developed electrolyte offers a promising solution for high-voltage lithium metal batteries.
• This molecule-to-system strategy provides a pathway for next-generation energy storage devices.