Poly(ethylene) Oxide Electrolytes for All-Solid-State Lithium Batteries Using Microsized Silicon/Carbon Anodes with...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Silicon (Si) anodes offer high capacity for lithium-ion batteries (LIBs) but suffer from poor stability with liquid electrolytes.
• All-solid-state lithium batteries (ASSLBs) using solid electrolytes are a promising alternative to overcome these limitations.
• Developing stable and high-performance silicon-based anodes for ASSLBs remains a key challenge.

Purpose of the Study:

• To investigate the performance of modified microsized porous silicon/carbon (Si/C) electrodes in poly(ethylene) oxide (PEO)-based ASSLBs.
• To evaluate the impact of electrode pre-treatment (pristine, prelithiated, preinfiltrated) on electrochemical performance.
• To understand the role of electrolyte mechanical stability versus ionic conductivity in ASSLB performance at elevated temperatures.

Main Methods:

• Fabrication of three types of Si/C electrodes: pristine, prelithiated with liquid electrolyte, and preinfiltrated with polymer electrolyte.
• Assembly of ASSLBs using these electrodes paired with PEO-based solid electrolytes.
• Electrochemical characterization including cycling performance, specific capacity, and Coulombic efficiency at 60 °C.

Main Results:

• Mechanical stability of the PEO electrolyte was found to be more critical than ionic conductivity for ASSLB performance at 60 °C.
• Both prelithiated and preinfiltrated Si/C electrodes exhibited higher specific capacity than pristine electrodes due to improved active material utilization.
• A solid-state half-cell with a preinfiltrated Si/C electrode achieved ~1,000 mAh g⁻¹ after 100 cycles at 800 mA g⁻¹ and 60 °C, with >98.9% average Coulombic efficiency.

Conclusions:

• Electrode pre-treatment strategies, particularly pre-infiltration with polymer electrolyte, significantly enhance the performance of Si/C anodes in ASSLBs.
• Rational design of electrode microstructure is crucial for optimizing interfacial lithium-ion transport and achieving high-performance ASSLBs.
• This approach offers a viable pathway for developing advanced silicon-based anodes for next-generation solid-state batteries.