High Volumetric Capacity FeS₂/SPAN Composite with Promoted Kinetics for Li-S Battery

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Sulfurized polyacrylonitrile (SPAN) offers solid-phase conversion in carbonate electrolytes, preventing polysulfide dissolution and self-discharge.
• Limitations of SPAN include low sulfur content, sluggish redox kinetics, and poor volumetric energy density, hindering its practical application.

Purpose of the Study:

• To enhance the electrochemical performance of SPAN by incorporating FeS2 nanodots and carbon nanotubes.
• To improve dynamic performance, volumetric capacity, and stability of sulfur-based cathodes at higher sulfur content.

Main Methods:

• Fabrication of a FeS2/SPAN composite cathode using spray granulation.
• Characterization of the composite's structure, ion/electron transport channels, and cathode interface stability.
• Electrochemical testing including cycling stability, rate performance, and volumetric capacity measurements at high mass loading.

Main Results:

• The FeS2/SPAN composite cathode demonstrated a high specific capacity of 683.56 mAh g-1 after 140 cycles at 0.5 C with 91.90% capacity retention.
• Achieved a volumetric capacity of 716.19 Ah L-1 at 0.2 C with a high areal mass loading of 6.1 mg cm-2.
• The spray granulation method resulted in interspersed secondary particles, facilitating ion/electron transport and a stable cathode interface.

Conclusions:

• The FeS2/SPAN composite effectively addresses the limitations of pure SPAN, offering improved electrochemical performance.
• This approach provides a viable strategy for developing high-energy-density sulfur-based cathode materials for advanced batteries.
• The enhanced dynamic performance and volumetric capacity at high sulfur loading pave the way for next-generation energy storage solutions.