Metal-Organic Framework Electrolytes for Sub- -60°C Solid-State Lithium Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Chemistry

Background:

• Conventional solid-state electrolytes (SSEs) face significant challenges in maintaining lithium-ion conductivity at ultralow temperatures (< -60°C).
• Polymeric and inorganic SSEs exhibit poor performance in extreme cold, limiting the operational range of solid-state lithium batteries (SSLBs).

Purpose of the Study:

• To design and fabricate a novel SSE material capable of efficient Li+ transport at ultralow temperatures.
• To develop an electron-cloud-homodistributed metal-organic framework (ECH-MOF) for advanced SSLB applications.

Main Methods:

• Fabrication of ECH-MOF with specific metal nodes and organic ligands to achieve electron cloud homodistribution.
• Characterization of Li+ transport mechanisms, revealing a quantum-tunneling-like slipping manner.
• Electrochemical testing of assembled SSLBs at ultralow temperatures (-60°C).

Main Results:

• The ECH-MOF SSE demonstrated ultralow activation energy (Ea) of 0.045 eV and Li+ conductivity of 1.2 × 10^-5 S cm^-1 at -60°C.
• An assembled NCM 811||Li half-cell maintained 62% capacity after 1000 cycles at -60°C and 1C.
• The developed SSE extends the operational envelope of SSLBs into the ultralow-temperature regime.

Conclusions:

• ECH-MOFs offer a promising solution for ultralow-temperature SSLB operation due to their unique Li+ transport properties.
• The electron-cloud homogenization strategy provides a versatile platform for developing next-generation ionic conductors.
• This research paves the way for reliable battery performance in extreme cold environments.