Exploring the Effects of the Spatial Distribution of Catalytic Sites on Sulfur Nucleation Behaviors and Electrochemical Performances of Lithium–Sulfur Batteries

Abstract

Achieving 3D Li2S morphologies and accelerating polysulfide conversion reactions are critical for realizing high-energy lithium–sulfur (Li–S) batteries. Although electrolytes containing high Gutmann donor number components facilitate transition from film-like to 3D Li2S morphologies, challenges arising from polysulfide diffusion and incomplete polysulfide conversion remain unresolved. Catalyst design strategies optimized for high donor electrolyte systems are essential in overcoming these limitations, yet they have garnered limited attention. Here, the influence of catalytic site distribution is systematically investigated as a key variable in catalyst design principles for high donor systems, aiming to achieve high-capacity and stable Li–S battery operation. Two types of carbon model systems are designed and employed in Li–S cells. One type features widespread distribution of catalytic sites, whereas the other incorporates localized catalytic sites. Experimental results demonstrate that spatial confinement of catalytic sites facilitates effective polysulfide redox reactions and supports the formation of 3D Li2S morphologies, even more pronounced in high donor electrolytes, thereby achieving near-theoretical capacity of sulfur (1630 mA h g−1) and ensuring stable cycling. These findings highlight that spatial control of catalytic sites is a key parameter for optimizing next-generation Li–S battery performances, offering novel design principles for advanced battery systems.