A Comprehensive Analysis of Lithium–Sulfur Batteries: Properties, Challenges, and Applications

Lithium–sulfur (Li–S) batteries have emerged as a promising next-generation energy storage solution as the capacity demands on lithium-ion systems begin to exceed practical limits. In a global push for renewable energy and sustainable practices, Li–S technology offers several compelling advantages. Both lithium and sulfur are relatively inexpensive (especially compared to the transition metals used in lithium-ion cells), and Li–S batteries are easier and less costly to recycle. Moreover, Li–S chemistry carries a theoretical energy density about five times greater than that of current lithium-ion batteries, making it attractive for high-energy-density applications. Because of these advantages, research interest in Li–S batteries remains high despite significant challenges that still limit their performance and lifespan. However, despite these advantages, several fundamental challenges limit the practical deployment of Li–S batteries, including the polysulfide shuttle effect, large volume expansion of sulfur during cycling, low intrinsic electrical conductivity of sulfur and its discharge products, and instability of the lithium metal anode caused by dendrite formation. This paper explains the working principles of Li–S batteries, analyzes the key challenges and recent achievements in their development, and surveys various mechanical engineering applications for which Li–S batteries are being explored, as well as prospects for their future commercialization and sustainability.