Hybrid Dynamic Covalent Network as a Protective Layer and Solid-State Electrolyte for Stable Lithium-Metal Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Chemistry

Background:

• Lithium metal anodes offer high energy density but suffer from dendrite growth and unstable solid electrolyte interphase (SEI) layers, hindering commercialization.
• Developing protective layers and solid-state electrolytes is crucial for stable and safe lithium metal batteries.

Purpose of the Study:

• To design and synthesize a chemically grafted hybrid dynamic network (CHDN) for use as a protective layer and hybrid solid-state electrolyte (HSE).
• To evaluate the electrochemical performance and safety of CHDN-based protective layers and HSEs in lithium metal batteries.

Main Methods:

• Synthesis of CHDN via cross-linking of a polymer matrix with functionalized SiO2 nanoparticles.
• Characterization of CHDN properties, including self-healing, mechanical robustness, and interfacial compatibility.
• Electrochemical testing of lithium metal half-cells and full cells (LiFePO4) with CHDN protection and HSEs.

Main Results:

• The CHDN exhibits self-healing, recyclability, and mechanical robustness due to dynamic disulfide bonds and chemical grafting.
• CHDN-protected Li metal anodes show superior electrochemical performance, with 83.7% capacity retention over 400 cycles in LiFePO4 full cells.
• CHDN-based solid-state cells achieve 89.5% capacity retention over 500 cycles and demonstrate excellent safety under physical damage.

Conclusions:

• The developed CHDN serves as an effective protective layer and HSE for stable lithium metal batteries.
• The hybrid dynamic network design principle offers a promising strategy for advanced battery materials.
• This work paves the way for next-generation high-energy-density batteries with improved safety and longevity.