Stabilized Solid Electrolyte Interface Layer and Regulate the Li⁺ Flux for Dendrite-Free Lithium Metal Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Disordered polyolefin separators in lithium metal batteries fail to control lithium dendrite formation.
• Lithium dendrites compromise the safety and practical application of these batteries.

Purpose of the Study:

• To develop a modified separator that inhibits lithium dendrite growth.
• To enhance the stability and performance of lithium metal batteries.

Main Methods:

• Modification of polyethylene (PE) separators with calcium carbonate (CaCO3) and cobalt phthalocyanine (CoPc).
• Density functional theory (DFT) calculations to understand ion interaction.
• Electrochemical cycling tests of modified separators in Li|Li, Li|Cu, and LiFePO4|Li cells.

Main Results:

• CaCO3 reacts with by-products, stabilizing the solid electrolyte interface (SEI).
• DFT calculations confirm CaCO3 and CoPc enhance Li+ deposition and dendrite-free growth.
• Modified separators show excellent cycle stability, with Li|CaCO3@CoPc@PE|Li cells cycling over 1550 hours and LiFePO4|CaCO3@CoPc@PE|Li cells retaining 98.65% capacity after 300 cycles at 2C.

Conclusions:

• The CaCO3@CoPc@PE modified separator effectively inhibits lithium dendrite growth.
• This approach offers a promising strategy for improving lithium metal battery safety and longevity.