Chemical Interaction Customized Metal-Organic Framework Enables Regulated Conductive Network for Selective Superionic...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Solid-state electrolytes (SSEs) are critical for safer, high-performance solid-state batteries.
• Achieving high ionic conductivity, Li+ selectivity, and electrochemical stability simultaneously in processable, air-tolerant SSEs remains a significant challenge.
• Existing SSEs often compromise on key performance metrics, hindering widespread adoption.

Purpose of the Study:

• To engineer novel chemical-interaction-customized metal-organic frameworks (CIC-MOF-X) as advanced SSEs.
• To create a regulated polar network with programmable host-guest interactions for enhanced ion transport.
• To demonstrate a new strategy for developing selective superionic conductors through coordination-structure engineering.

Main Methods:

• Nanoconfined polymerization of a polar guest matrix within functionalized MOF nanochannels.
• Decoration of CIC-MOF-OH with hydroxy groups to tailor host-guest interactions.
• Characterization of ionic conductivity, Li+ transference number, air stability, and electrochemical performance in Li plating/stripping and full cells.

Main Results:

• CIC-MOF-OH achieved high ionic conductivity (6.1 × 10-4 S cm-1) and Li+ transference number (0.7 at 30 °C).
• The material demonstrated excellent air stability, retaining conductivity after 30 days in humid air.
• Stable Li plating/stripping for 1600 hours and high capacity retention in LiFePO4|Li (96.5%) and NCM811|Li (83% after 150 cycles) full cells were achieved.

Conclusions:

• Coordination-structure engineering in porous crystals offers a general route to selective superionic conduction.
• The developed CIC-MOF-OH material addresses key limitations in current SSEs, paving the way for improved solid-state batteries.
• This approach enables the development of processable, air-tolerant SSEs with a desirable combination of high ionic conductivity and Li+ selectivity.