Low-Cost GeO₂-Derived LAGP Nanofiber Enhanced Composite Solid Electrolytes Enabling High-Performance Solid-State...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Composite solid electrolytes (CSEs) combine ceramic and polymer properties for improved performance.
• Nanofibers (NFs) in polymer matrices can create efficient ion conduction pathways.
• Lithium metal batteries (LMBs) require stable and conductive solid electrolytes.

Purpose of the Study:

• To synthesize novel lithium aluminum germanium phosphate (LAGP) ceramic nanofibers (NFs) using an economical electrospinning method.
• To optimize LAGP NFs loading in polymer matrices for enhanced composite solid electrolyte (CSE) properties.
• To evaluate the performance of CSEs and their application in solid-state lithium metal batteries.

Main Methods:

• Cost-effective electrospinning of GeO2 precursor for LAGP NFs synthesis.
• Systematic optimization of calcination temperatures and NFs loading in PVDF-HFP matrices.
• Characterization of ionic conductivity, electrochemical stability window (ESW), activation energy (Ea), and lithium-ion transference number (tLi+).
• Fabrication and testing of LiFePO4 (LFP)/CSE(15NFs) interfaces in solid-state LMBs.

Main Results:

• First-time synthesis of LAGP NFs from GeO2 precursor, reducing raw material costs by ~80%.
• Optimized CSE with 15 wt% LAGP NFs (CSE(15NFs)) achieved ionic conductivity of 2.22 × 10^-4 S·cm^-1 at 20 °C.
• CSE(15NFs) exhibited an ESW > 4.8 V, low Ea (0.32 eV), and high tLi+ (0.52).
• LFP/CSE(15NFs) based LMBs showed improved rate capability and retained 83.7% capacity after 200 cycles at 0.2 C.

Conclusions:

• Low-cost GeO2-derived LAGP NFs are viable for high-performance CSEs.
• Optimized CSEs offer a promising pathway for advanced solid-state lithium batteries.
• This work demonstrates significant potential for practical applications in energy storage devices.