Organic-Inorganic Dual-Network Composite Separators for Lithium Metal Batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Commercial polyolefin separators have poor ionic conductivity, leading to lithium dendrite growth and safety issues in lithium metal batteries.
• Developing advanced separators is crucial for improving the performance and safety of next-generation batteries.

Purpose of the Study:

• To design and fabricate a novel organic-inorganic composite separator to enhance ion transport and suppress lithium dendrite formation.
• To investigate the synergistic effects of hydroxyapatite (HAP) nanowires and poly(m-phenylene isophthalamide) (PMIA) for improved battery performance.

Main Methods:

• Fabrication of a composite separator using electrospun poly(m-phenylene isophthalamide) (PMIA) membrane coated with hydroxyapatite (HAP) nanowires.
• Characterization of the separator's ionic conductivity, lithium-ion transference number, and morphology.
• Evaluation of battery performance using lithium symmetric cells and LiFePO4||Li cells.

Main Results:

• The 19 µm HAP/PMIA composite separator achieved high ionic conductivity (0.68 mS cm⁻¹) and a lithium-ion transference number of 0.51.
• Lithium symmetric cells demonstrated a lifespan over 1000 hours with low polarization, outperforming commercial separators.
• LiFePO4||Li cells showed 97.3% capacity retention after 200 cycles and excellent rate capability.

Conclusions:

• The HAP/PMIA composite separator effectively enhances ion transport and suppresses lithium dendrite growth.
• This novel separator offers a promising solution for improving the safety and performance of lithium metal batteries.
• The synergistic interaction between HAP and PMIA is key to achieving superior electrochemical properties.