Unity of Opposites between Soluble and Insoluble Lithium Polysulfides in Lithium-Sulfur Batteries

Rechargeable batteries based on Li-S chemistry show promise as being possible for next-generation energy storage devices because of their ultrahigh capacities and energy densities. Research over the past decade has demonstrated that the morphology of lithium polysulfides (LPSs) in electrolytes (soluble or insoluble) plays a decisive role in battery performance. Early studies have focused mainly on inhibiting the dissolution of LPSs and invested considerable effort to realize this objective. However, in recent years, a completely different view that the dissolution of LPSs during battery discharge/charge should be promoted has emerged. At this critical juncture in the large-scale application of Li-S batteries, it is time to summarize and discuss both sides of the contradiction. Herein, an overview of these two opposite views pertaining to soluble and insoluble LPSs, including their historical environment, classical strategies, advantages, and disadvantages. Finally, the future morphology of LPSs in Li-S batteries is predicted based on a multiangle review of research studies conducted thus far, and the reasoning behind this conjecture is thoroughly discussed.

Automated summary

This article discusses the influence of the morphology of lithium polysulfides (LPSs) on the performance of lithium-sulfur batteries and summarizes the earlier studies on inhibiting LPS dissolution as well as the recent viewpoint of promoting LPS dissolution. The article provides an overview of the historical background, strategies, advantages, and disadvantages of the two views, and predicts the future morphology of LPSs in lithium-sulfur batteries based on existing research.