Graphdiyne-like Porous Organic Framework as a Solid-Phase Sulfur Conversion Cathodic Host for Stable Li-S Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Solid-phase sulfur conversion polymer cathodes offer advantages for Li-S batteries, including stability and fast ion transfer.
• Existing materials like sulfurized polyacrylonitrile (SPAN) and polyaniline (SPANI) have low sulfur content and poor cycling performance due to surface sulfurization.
• Limitations in current cathode materials hinder the full potential of Li-S batteries.

Purpose of the Study:

• To synthesize a novel graphdiyne-like porous organic framework (GPOF) as a host for solid-phase sulfur conversion.
• To enhance sulfur content and improve cycling stability in Li-S battery cathodes.
• To develop a facile method for producing advanced sulfur conversion polymer cathodes.

Main Methods:

• Synthesis of a graphdiyne-like porous organic framework (GPOF).
• GPOF used as a host material for solid-phase sulfur conversion.
• Electrochemical testing of the sulfurized GPOF cathode (SGPOF-320) in Li-S batteries.

Main Results:

• GPOF features abundant unsaturated bonds for binding sulfur chains, enabling high active sulfur content.
• Microporous structure of GPOF accommodates volume expansion, ensuring long-term cycling stability.
• SGPOF-320 cathode shows negligible capacity fade after 250 cycles at 0.2 C, with an average discharge capacity of 925 mA h g^-1.

Conclusions:

• The developed SGPOF-320 cathode exhibits superior electrochemical stability and performance for Li-S batteries.
• This work presents a facile approach for creating high-performance sulfur conversion polymer cathodes.
• The findings pave the way for exploring new cathode materials for advanced Li-S battery applications.