Macroscopically uniform interface layer with Li⁺ conductive channels for high-performance Li metal batteries

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Grain boundaries in solid electrolyte interfaces cause non-uniform lithium metal deposition, hindering full-battery performance.
• Developing stable and efficient lithium metal anodes is crucial for next-generation energy storage.

Purpose of the Study:

• To engineer a lithium-ion selective transport layer for dendrite-free lithium metal anodes.
• To enhance the performance and cycle life of lithium metal batteries.

Main Methods:

• Layer-by-layer assembly of protonated carbon nitride nanosheets.
• Characterization of the uniform macroscopic structure and ordered pores.
• Electrochemical testing of pouch cells and large-capacity cells.

Main Results:

• The carbon nitride layer provided high-speed, low-tortuosity lithium-ion transport channels.
• A 324 Wh/kg pouch cell achieved 300 stable cycles with 90.0% capacity retention and 99.7% Coulombic efficiency.
• A 7 Ah cell demonstrated high energy density (506 Wh/kg) and 160 cycles, enabling current collector-free anodes.

Conclusions:

• A macroscopically uniform interface layer with ion-conductive channels is key to high-performance lithium metal batteries.
• The developed carbon nitride layer offers a promising strategy for advanced lithium metal anodes.
• This approach paves the way for batteries with high energy density and extended cycle life.