Ceramic-in-Polymer Hybrid Electrolytes with Enhanced Electrochemical Performance

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Rechargeable lithium metal batteries require advanced electrolytes to overcome challenges like polarization and dendrite growth.
• Single-ion conducting polymers offer potential but can be mechanically rigid, necessitating ion mobilizers that may lead to inhomogeneous transport and short circuits.
• Developing stable and efficient electrolytes is crucial for advancing lithium metal battery technology.

Purpose of the Study:

• To explore ceramic-in-polymer hybrid electrolytes for improved lithium metal battery performance.
• To investigate the effect of silane-functionalized LATP particles and polymer blends on electrolyte properties.
• To assess the electrochemical stability and cycling performance of the developed hybrid electrolyte.

Main Methods:

• Fabrication of hybrid electrolytes using polymer blends (single-ion conducting polymer and PVdF-HFP), swelling agents (EC/PC), and silane-functionalized LATP particles.
• Characterization of the electrolyte's interphase stability with Li metal, including deposition tests.
• Evaluation of ionic conductivity and solvent uptake.
• Electrochemical performance testing in LiNi0.6Co0.2Mn0.2O2 (NMC622)||Li metal cells, with and without LiNbO3 cathode coating.

Main Results:

• The hybrid electrolyte formed an oxide-rich layer, stabilizing the interphase with Li metal and enabling stable lithium deposition for over 700 hours.
• Incorporated oxide particles reduced solvent uptake from 140 to 38 wt % while maintaining high ionic conductivity.
• Cells with the hybrid electrolyte showed impressive capacity retention over 300 cycles.
• A thin LiNbO3 coating on the cathode further boosted cycling stability, achieving 78% capacity retention over 600 cycles.

Conclusions:

• Ceramic-in-polymer hybrid electrolytes offer a promising strategy for stabilizing lithium metal anodes and improving battery lifespan.
• The developed hybrid electrolyte effectively reduces solvent uptake and enhances interfacial stability, addressing key limitations of polymer electrolytes.
• These findings highlight the significant potential of hybrid electrolyte concepts for next-generation high-performance rechargeable lithium metal batteries.