Double-layer Composite Gel Polymer Electrolyte for Organic Sodium-Metal Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Organic cathode materials offer sustainable advantages but suffer from dissolution issues in liquid electrolytes.
• Pyrene-4,5,9,10-tetraone (PTO) is a promising organic cathode material with high capacity but poor stability due to electrolyte solubility.
• Improving electrolyte stability is crucial for the practical application of organic sodium-metal batteries.

Purpose of the Study:

• To develop a stable electrolyte for organic sodium-metal batteries utilizing pyrene-4,5,9,10-tetraone (PTO).
• To investigate the performance of a novel double-layer composite gel polymer electrolyte (DLCGPE) in PTO-based sodium-metal batteries.
• To address the electrolyte-induced dissolution of PTO and enhance battery cycling stability.

Main Methods:

• Fabrication of a double-layer composite gel polymer electrolyte (DLCGPE) combining poly(ionic liquid) and plastic crystal electrolytes.
• Characterization of DLCGPE ionic conductivity (2.17×10⁻⁴ S cm⁻¹) and electrochemical window (4.8 V).
• Assembly and testing of sodium-symmetric and PTO/Na organic sodium-metal batteries using the developed DLCGPE.

Main Results:

• The DLCGPE demonstrated excellent interfacial stability in sodium-symmetric batteries over 500 hours.
• PTO/Na batteries with DLCGPE retained a specific capacity of 201 mAh g⁻¹ after 300 cycles.
• The DLCGPE effectively inhibited PTO dissolution, leading to improved battery longevity and performance.

Conclusions:

• The developed DLCGPE successfully mitigates PTO dissolution in organic sodium-metal batteries.
• This composite electrolyte significantly enhances the cyclic stability and capacity retention of PTO-based batteries.
• The study highlights the potential of asymmetric electrolytes for advancing organic secondary battery technology.