Binder-free and high-loading sulfurized polyacrylonitrile cathode for lithium/sulfur batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Sulfurized polyacrylonitrile (SPAN) is a key material for Li/S batteries, offering high sulfur utilization and cyclability.
• Current SPAN electrode fabrication methods using powders necessitate excess electrolyte, conductive agents, and binders, limiting practical energy density.

Purpose of the Study:

• To enhance the practical energy density of Li/S batteries.
• To develop a novel fabrication method for SPAN electrodes.

Main Methods:

• Fabrication of bulk-type SPAN disk cathodes from pressed sulfur and polyacrylonitrile powders via a heating process.
• Direct use of SPAN disks as cathode materials, leveraging their π-π structures for electrical connectivity.
• Incorporation of multi-walled carbon nanotubes (MWCNTs) as a conductive agent.

Main Results:

• The fabricated SPAN disk electrodes demonstrated interconnected pores, improving Li+ ion mobility and electrolyte adsorption.
• The optimal electrode achieved a high specific capacity of 517 mA h g_electrode^-1.
• The Li/S cell achieved a practical energy density of 250 W h kg^-1 and high areal capacity (8.5 mA h cm^-2) with high SPAN loading (16.37 mg cm^-2).
• Addition of 10 wt% MWCNTs improved cyclability while maintaining high energy density.

Conclusions:

• The bulk-type SPAN disk cathode strategy significantly improves practical energy density in Li/S batteries.
• This approach offers a viable pathway for developing high-performance Li/S batteries.
• The direct use of SPAN disks simplifies electrode fabrication and enhances electrochemical properties.