Electron Redistribution Enables Redox-Resistible Li₆ PS₅ Cl towards High-Performance All-Solid-State Lithium...

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Batteries

Background:

• Sulfide electrolytes offer high ionic conductivity for all-solid-state lithium batteries.
• Parasitic redox reactions at the electrolyte-lithium metal interface cause instability and performance degradation.

Purpose of the Study:

• To create a redox-resistible sulfide electrolyte by modifying the electronic structure of Li6PS5Cl (LPSC).
• To enhance interfacial stability and battery performance in solid-state lithium batteries.

Main Methods:

• Incorporation of Magnesium (Mg) and Fluorine (F) into the Li6PS5Cl (LPSC) electrolyte.
• Investigating the electronic structure modulation and its effect on redox reactions.
• Fabricating and testing LiCoO2/Li6PS5Cl-MgF2/Li battery cells.

Main Results:

• The modified LPSC electrolyte (LPSC-MgF2) demonstrated resistance to parasitic redox reactions with lithium metal.
• Mg incorporation led to electron agglomeration around sulfur atoms, inhibiting lithium metal oxidation.
• F incorporation formed a self-limiting interface, further suppressing detrimental redox reactions.
• The LPSC-MgF2 electrolyte exhibited a 2.3 times higher critical current density compared to the pristine electrolyte.
• The LiCoO2/LPSC-MgF2/Li cell achieved 93.3% capacity retention after 100 cycles at 0.2 C.

Conclusions:

• Electronic structure modulation of sulfide electrolytes is an effective strategy to overcome interfacial redox issues.
• The developed Mg and F co-doped LPSC electrolyte shows significant potential for stable and high-performance all-solid-state lithium batteries.