Long-Life Lithium-Ion Sulfur Pouch Battery Enabled by Regulating Solvent Molecules and Using Lithiated Graphite Anode

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium-sulfur (Li-S) batteries face limitations from the shuttle effect and Li-metal anode instability.
• Li-ion S batteries (LISBs) using graphite (Gr) anodes offer a more stable alternative for long cycle life.
• Graphite anodes are often incompatible with ether-based electrolytes due to Li+-ether complex co-intercalation.

Purpose of the Study:

• To develop a strategy for enhancing graphite anode compatibility in Li-S batteries.
• To suppress the shuttle effect and improve the stability of Li-ion S batteries.
• To achieve long-cycle life and high performance in LISBs.

Main Methods:

• Solvent molecule structure regulation to weaken Li+-solvent binding via steric hindrance and electronegativity.
• Accelerating Li+ de-solvation and preventing Li+-ether complex co-intercalation into graphite anodes.
• Utilizing weakly solvating solvents to suppress polysulfide shuttle and form stable anion-derived solid electrolyte interfaces on graphite.

Main Results:

• A LISB coin-cell with a lithiated graphite anode and S@C cathode maintained a stable capacity of ~770 mAh g-1 over 200 cycles.
• A practical LISB pouch-cell with high graphite loading (~10.5 mg cm-2) achieved an initial capacity of 802.3 mAh g-1.
• The pouch-cell demonstrated a stable capacity of 499.1 mAh g-1 with 95.9% Coulombic efficiency after 120 cycles.

Conclusions:

• Solvent molecule structure regulation effectively enhances graphite anode performance in Li-S batteries.
• The developed strategy enables stable cycling and suppresses the shuttle effect in LISBs.
• This approach paves the way for practical, long-lasting Li-ion S batteries with high energy density.