Enhancing Volumetric Energy Density in Lithium–Sulfur Batteries through Highly Dense, Low Tortuosity Sulfur Electrodes

Abstract

Recent advancements in Lithium–sulfur (Li─S) batteries have significantly improved cell-specific energy, while challenges persist in improving volumetric energy and cell cycle life. In this study, a design principle is elucidated to enhance sulfur utilization in high-density and high-sulfur-content electrodes using a liquid-templated shear-rolling method. The findings indicate that a vascular-like hierarchical electrode structure and compatible liquid electrolytes are critical for improving electrolyte permeability in dense electrodes, achieving high sulfur utilization (>1200 mAh g⁻¹) under practical conditions (47% cathode porosity, S loading 4.5 mg cm⁻², S content 70%, E/S 4 mL g⁻¹). Li─S pouch cells are demonstrated with an exceptionally high volumetric energy density (668 Wh L⁻¹) and extended cycle life by integrating the optimized electrode structures and electrolytes. This study advances understanding and design of high volumetric energy Li─S cells. Additionally, the proposed templated shear-rolling technique shows potential for application in the fabrication of other high-energy electrodes.