Conformal zwitterionic polymer nanofilms and lithium batteries

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Chemistry

Background:

• Solid-electrolyte interphases (SEIs) are critical for rechargeable battery stability.
• Ion and molecule transport through SEIs dictates cycling performance in high-energy batteries.
• Electrolyte decomposition often limits battery operation due to electroreduction beyond stability limits.

Purpose of the Study:

• To develop scalable synthesis of electrochemically inert nanofilms for precise control of SEIs.
• To engineer gradient zwitterionic polymer (G-ZWP) interphases for regulating transport and electroreduction kinetics at Li-metal anodes.
• To achieve stable cycling in high-energy rechargeable batteries using novel interphases.

Main Methods:

• Scalable solvent-free synthesis combining initiated chemical vapor deposition and diffusion-limited vapor derivatization.
• Formation of a zwitterionic top layer with high ionic conductivity.
• Creation of an inner covalently cross-linked layer for solvent blocking and stability at reducing potentials.

Main Results:

• Nanometer-thick G-ZWP interphases demonstrated stable cycling of Cu substrates for over 2000 hours at 1 mA/cm².
• Achieved stable long-term cycling of Li batteries (N/P ratio 0 to 2.5) and Li-dry-air batteries (10 mA·hour/cm²).
• Successfully stabilized sodium (Na) and zinc (Zn) electrodeposition.

Conclusions:

• Gradient zwitterionic polymer interphases offer a scalable solution for designing stable SEIs.
• The G-ZWP interphases effectively regulate transport and electroreduction, enhancing battery cycling stability.
• This approach enables rational design for next-generation high-energy rechargeable batteries.