Improved lithium-sulfur cells with a treated carbon paper interlayer.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium-sulfur (Li-S) batteries offer high theoretical energy density but suffer from poor cycle stability and low sulfur utilization.
• Dissolution of polysulfide intermediates and limited conductivity are key challenges hindering Li-S battery performance.

Purpose of the Study:

• To investigate a simple, low-cost method to enhance Li-S cell performance using a modified carbon paper interlayer.
• To improve sulfur host material properties and mitigate polysulfide shuttle effects.

Main Methods:

• A commercial carbon paper was treated using an alcohol-alkaline/thermal process to introduce functional groups and micro-cracks.
• The treated carbon paper was incorporated as an interlayer between the sulfur electrode and separator in Li-S cells.
• Electrochemical performance was evaluated through galvanostatic cycling, and material characterization was performed using SEM and EDS.

Main Results:

• The modified Li-S cells exhibited a higher initial capacity (1651 mAh g(-1) at C/5) compared to control cells.
• The treated carbon paper interlayer significantly improved capacity retention over 100 cycles at various rates (e.g., 1057 mAh g(-1) at C/5, 1.8 V cut-off).
• SEM and EDS confirmed the 3D architecture of the interlayer effectively trapped sulfur species.

Conclusions:

• The alcohol-alkaline/thermal treated carbon paper interlayer effectively enhances Li-S cell performance by improving conductivity and trapping soluble sulfur species.
• This low-cost modification presents a viable strategy to overcome critical challenges in Li-S battery technology.
• The developed interlayer shows potential for practical applications in high-energy-density batteries.