Toward Practical High-Energy-Density Lithium–Sulfur Pouch Cells: A Review

Lithium–sulfur (Li–S) batteries promise great potential as high-energy-density energy-storage devices due to their ultrahigh theoretical energy density of 2600 Wh kg⁻¹. Evaluation and analysis on practical Li–S pouch cells are essential for achieving actual high energy density under working conditions and affording developing directions for practical applications. This review aims to afford a comprehensive overview of high-energy-density Li–S pouch cells regarding 7 years of development and to point out further research directions. Key design parameters to achieve actual high energy density are addressed first, to define the research boundaries distinguished from coin-cell-level evaluation. Systematic analysis of the published literature and cutting-edge performances is then conducted to demonstrate the achieved progress and the gap toward practical applications. Following that, failure analysis as well as promotion strategies at the pouch cell level are, respectively, discussed to reveal the unique working and failure mechanism that shall be accordingly addressed. Finally, perspectives toward high-performance Li–S pouch cells are presented regarding the challenges and opportunities of this field.