Cation-polymerized artificial SEI layer modified Li metal applied in soft-matter polymer electrolyte.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium metal batteries with polymer electrolytes offer high safety and energy density but suffer from dendrite formation and uneven lithium deposition.
• Surface modification of lithium metal anodes is crucial for improving battery performance and cycle life.

Purpose of the Study:

• To prepare an artificial solid electrolyte interface (SEI) modified lithium metal anode.
• To evaluate the electrochemical performance and stability of the modified lithium metal anode in polymer electrolyte batteries.

Main Methods:

• An artificial SEI was created on the lithium metal anode via a cation-polymerization process, initiated by PF5 generated from CsPF6.
• Performance was tested using Li||Li symmetric cells and Li||NCM 622 full cells with a soft-matter polymer electrolyte.

Main Results:

• The artificial SEI-modified lithium metal anode demonstrated stable polarization voltage with a low over-potential (25 mV) after 3000 hours at 1.5 mA cm-2 in Li||Li symmetric cells.
• Li||NCM 622 full cells with the modified anode showed significantly improved electrochemical performance, retaining 75% capacity after 120 cycles at a current density of 1.5 mA cm-2.

Conclusions:

• The artificial SEI effectively suppresses uneven lithium deposition, enhancing the stability and cycle life of lithium metal batteries with polymer electrolytes.
• This surface modification strategy shows promise for the commercialization of high-performance, safe lithium metal batteries.