Dual-Functional Asymmetric PDOL-Based Gel Polymer Electrolyte for High-Performance Lithium-Sulfur Batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium-sulfur (Li-S) batteries offer high energy density but suffer from lithium polysulfide (LiPSs) shuttling and lithium dendrite growth.
• These issues lead to poor cycle life and safety concerns, hindering practical applications.

Purpose of the Study:

• To develop an in situ formed asymmetric gel polymer electrolyte (GPE) to address LiPSs shuttling and lithium dendrite formation in Li-S batteries.
• To enhance the stability, cycle life, and safety of Li-S batteries through electrolyte engineering.

Main Methods:

• Fabrication of an asymmetric GPE with a PDOL-PSN cathode layer and a PDOL-LLZO anode layer.
• Utilized Lewis acid-base interactions for LiPSs anchoring and promoted uniform Li+ transport and deposition.
• Employed molecular dynamics and density functional theory simulations to investigate the suppression mechanism.

Main Results:

• The asymmetric GPE demonstrated stable cycling for over 2200 hours in Li//Li symmetric cells.
• Li-S full cells achieved a high initial discharge capacity of 1062.1 mAh g-1 with 87.9% capacity retention after 100 cycles.
• Coulombic efficiency remained above 96.6%, indicating effective suppression of side reactions.

Conclusions:

• The developed asymmetric GPE effectively mitigates LiPSs shuttling and promotes uniform Li+ behavior.
• This strategy offers a viable pathway for designing advanced electrolytes for high-performance and durable Li-S batteries.