A Metal-Organic-Framework-Based Electrolyte with Nanowetted Interfaces for High-Energy-Density Solid-State Lithium...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Solid-state batteries (SSBs) offer enhanced safety but face challenges with interfacial impedance, limiting Li+ transport kinetics.
• Poor interfacial contact between solid electrolytes and electrodes hinders achieving high active loading and energy density in SSBs.

Purpose of the Study:

• To develop a novel solid-like electrolyte (SLE) to overcome interfacial limitations in solid-state batteries.
• To enhance Li+ transport kinetics and electrochemical performance by addressing interfacial resistance.

Main Methods:

• Synthesized a novel solid-like electrolyte (SLE) composed of ionic-liquid-impregnated metal-organic framework nanocrystals (Li-IL@MOF).
• Characterized the electrochemical properties of the Li-IL@MOF SLE, including ionic conductivity and Li+ transference number.
• Integrated the Li-IL@MOF SLE into a rechargeable Li|LiFePO4 SSB and evaluated its performance at various temperatures and active loadings.

Main Results:

• The Li-IL@MOF SLE exhibited high room-temperature ionic conductivity (3.0 × 10-4 S cm-1) and an improved Li+ transference number (0.36).
• Demonstrated excellent compatibility with Li metal and active electrodes, resulting in low interfacial resistances.
• Achieved an unprecedented active loading of 25 mg cm-2 in a Li|LiFePO4 SSB, with remarkable performance from -20 °C to 150 °C.

Conclusions:

• The novel Li-IL@MOF SLE effectively mitigates interfacial impedance in solid-state batteries.
• The nanoconfined ionic liquid's interfacial wettability creates a 3D Li+ conductive network, crucial for high performance.
• This advancement paves the way for high-energy-density, safe solid-state batteries with broad operational temperature ranges.