Review of the Applications of Density Functional Theory Calculations in Lithium–Sulfur Batteries

Lithium–sulfur (Li-S) batteries, featuring a superior theoretical energy density of 2600 Wh/kg and a high specific capacity of 1675 mAh/g for sulfur cathodes, have emerged as a promising candidate for next-generation, high-energy-density energy storage technologies. Nevertheless, their commercialization has been hindered by some bottlenecks, including the polysulfide (LiPSs) shuttle effect, severe volume expansion, and sluggish reaction kinetics. Density Functional Theory (DFT), serving as an atomic-scale computational tool, offers essential theoretical assistance for clarifying the mechanisms and guiding the precision design of S cathode of Li-S batteries. This review focuses on the role of DFT in the mechanism of polysulfide conversion and the shuttle effect. By simulating the adsorption energy, charge density distribution, and reaction pathways of LiPSs using DFT calculations, the key reaction steps of polysulfide conversion can be clearly identified. In addition, DFT calculations also play a vital role in the inhibition of lithium dendrites and the regulation of the solid-electrolyte interphase (SEI) film. This review suggests that DFT calculations could provide more applications in the development of Li-S batteries.