An ultrathin ionomer interphase for high efficiency lithium anode in carbonate based electrolyte

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• High-energy lithium-ion batteries require stable lithium metal anodes, but face challenges with coulombic efficiency and dendrite formation in carbonate electrolytes.
• Developing effective strategies for uniform lithium plating and suppressing parasitic reactions is crucial for battery longevity and safety.

Purpose of the Study:

• To demonstrate an ultrathin ionomer membrane coating for efficient and stable lithium plating-stripping cycles on lithium metal anodes.
• To investigate the mechanism of electric field homogenization and parasitic reaction suppression by the ionomer coating.

Main Methods:

• Fabrication of an ultrathin lithium-ion ionomer membrane (≤100 nm) using sulfonated polyether ether ketone embedded with polyhedral oligosilsesquioxane.
• Coating the membrane on copper or lithium metal substrates.
• Utilizing operando analyses and theoretical simulations to study the coating's performance.
• Testing lithium plating-stripping cycles at room and elevated temperatures (50 °C).

Main Results:

• The ionomer coating effectively homogenizes the electric field over a large lithium plating surface, promoting uniform deposition.
• The membrane acts as an artificial solid-electrolyte interphase, minimizing parasitic reactions at the electrolyte-electrode interface.
• Dendrite-free lithium plating was achieved on copper with outstanding coulombic efficiencies at both room and elevated temperatures.

Conclusions:

• The developed ultrathin ionomer membrane coating is a promising solution for stable and efficient lithium plating-stripping cycles.
• The coated copper demonstrates potential as a current collector for high-quality pre-plated lithium thin-film anodes.
• This approach addresses key challenges in developing high-energy lithium-ion batteries with lithium metal anodes.