Argyrodite-Li₆PS₅Cl/Polymer-based Highly Conductive Composite Electrolyte for All-Solid-State Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Solid-state batteries (SSBs) using argyrodite-Li₆PS₅Cl (LPSCl) electrolytes offer an alternative to conventional lithium-ion batteries (LIBs).
• Key challenges include interfacial resistance and lithium dendrite growth due to poor contact between LPSCl and electrodes, hindering industrial adoption.
• Developing advanced electrolytes is crucial for improving SSB safety and performance.

Purpose of the Study:

• To develop a composite electrolyte based on LPSCl and a polymer to improve interfacial contact and suppress lithium dendrite formation.
• To investigate the effect of ball-milling on LPSCl morphology and its impact on composite electrolyte properties.
• To evaluate the electrochemical performance and cycling stability of the developed composite electrolytes in SSBs.

Main Methods:

• Fabrication of LPSCl/polymer composite electrolytes using in situ polymerization of triethylene glycol dimethacrylate (TEGDMA) around LPSCl.
• Modification of LPSCl ceramic morphology and particle size via ball-milling.
• Electrochemical characterization, including ionic conductivity measurements, Li-metal compatibility tests, and cycling performance evaluation in SSB configurations.

Main Results:

• The ball-milled LPSCl/polymer composite electrolyte exhibited higher ionic conductivity (2.21 × 10^-4 S/cm) than the as-received counterpart (1.65 × 10^-4 S/cm) at 25 °C.
• Both composite electrolytes demonstrated excellent Li-metal compatibility and superior cycling stability (1000 h) compared to bare LPSCl electrolytes (600 h).
• An SSB utilizing the ball-milled LPSCl/polymer composite electrolyte achieved high specific discharge capacity (138 mA h/g) and Coulombic efficiency (99.97%) with Li-Indium anodes and NMC811 cathodes.

Conclusions:

• The LPSCl/polymer composite electrolyte effectively enhances interfacial contact and suppresses lithium dendrite growth in solid-state batteries.
• Ball-milling pre-treatment of LPSCl further improves ionic conductivity and electrochemical stability.
• The developed composite electrolyte shows significant promise for the development of high-performance and safer solid-state batteries.