Enhanced Ionic Conductivity and Stability in Li₁₀SnP₂S₁₂ Solid Electrolytes via Tellurium Anionic Doping

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Chemistry

Background:

• Sulfide solid electrolytes are key for high-performance all-solid-state batteries.
• Li10SnP2S12 (LSPS) offers good conductivity and sustainability but needs improved stability.
• Balancing ionic transport and electrochemical stability remains a challenge.

Purpose of the Study:

• To synthesize and characterize tellurium-doped Li10SnP2S12 (LSPST) electrolytes.
• To investigate the effect of Te doping on ionic conductivity, activation energy, and electrochemical stability.
• To evaluate the performance of LSPST in all-solid-state battery full cells.

Main Methods:

• High-energy ball milling and gradient annealing for LSPST synthesis.
• Structural analysis (e.g., XRD) to confirm Te substitution.
• Electrochemical measurements (ionic conductivity, impedance spectroscopy) and theoretical calculations (DFT, MD simulations).
• Fabrication and testing of Li-In/LSPST/Li6PS5Cl/NCM811 full cells.

Main Results:

• Uniform Te substitution at S sites in Li10SnP2S12.
• Optimal Te doping (x=0.1) enhanced ionic conductivity by 45.2% (4.3 × 10^-3 S cm^-1) with lower activation energy (0.259 eV).
• Doping suppressed electronic conductivity, inhibited dendrites, and improved full-cell performance (136.1 mAh g^-1 initial capacity, 67.9% retention after 50 cycles).

Conclusions:

• Anionic doping with Te is an effective strategy to enhance both ionic transport and electrochemical stability in sulfide electrolytes.
• LSPST electrolytes offer a promising pathway for developing high-performance, cost-effective all-solid-state batteries.
• The study provides insights into structure-property relationships for optimizing sulfide solid electrolytes.