Disulfide-Assisted Organic Polysulfide Cathode Design Enables Improved Kinetics in Lithium-Sulfur Batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium-sulfur batteries (LSBs) face limitations due to the polysulfide shuttle effect and poor reaction kinetics.
• Developing cathodes with high sulfur loading and improved conductivity is crucial for advancing LSB technology.

Purpose of the Study:

• To synthesize a novel organic polysulfide composite cathode for high-performance LSBs.
• To address the shuttle effect and enhance electrochemical stability in LSBs.

Main Methods:

• Synthesized linear organic polysulfides (TMTD-S) via radical reaction between elemental sulfur and tetramethylthiuram disulfide (TMTD).
• Compounded TMTD-S with conductive carbon (ECP600JD) and fabricated paper-based electrodes.
• Investigated electrochemical performance, including capacity retention, rate capability, and lithium-ion diffusion coefficients.

Main Results:

• The TMTD-24S@ECP600JD cathode showed 79.1% capacity retention after 250 cycles at 0.2C, outperforming traditional S@ECP600JD (14.1%).
• The TMTD-54S@ECP600JD cathode (88 wt% sulfur) delivered an initial capacity of 941 mAh g⁻¹ at 0.2C with 82.1% retention after 200 cycles.
• High rate performance was demonstrated, with 638.3 mAh g⁻¹ at 2C, and the highest lithium-ion diffusion coefficient was observed.

Conclusions:

• The novel organic polysulfide cathode effectively mitigates the shuttle effect and improves kinetics in LSBs.
• The TMTD-54S@ECP600JD composite shows significant potential as a high-performance cathode material for advanced LSB applications.