Regulating Polysulfide Transformation and Deposition Kinetics in Lithium-Sulfur Batteries Based on 3D Conductive...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Polysulfide shuttle and slow liquid-solid conversion hinder lithium-sulfur (Li-S) battery practicality.
• Existing research on polysulfide kinetics has limitations in capturing implicit details.

Purpose of the Study:

• To design a novel conducting network for a 3D nucleation mode in Li-S batteries.
• To investigate the relationship between nucleation mode and liquid-solid transformation using in situ impedance.

Main Methods:

• Fabrication of FeN-NPC conducting network from hemin.
• Induction of a 3D nucleation mode for Li2S deposition.
• In situ impedance spectroscopy with Dynamic Random Termination (DRT) analysis.

Main Results:

• The 3D nucleation mode promotes higher Li2S deposition and earlier nucleation compared to 2D nucleation.
• In situ impedance reveals that the 3D nucleation mode provides ample growth sites, forming a Li2S layer without charge transfer limitations.
• Porous structure with nanotubes enhances Li+ diffusion.

Conclusions:

• The 3D nucleation strategy significantly enhances Li-S battery performance.
• Achieved high capacity (1423 mAh g-1 at 0.1 C), low capacity attenuation (0.029% per cycle at 2 C), and excellent rate capability (620 mAh g-1 at 5 C).