Sulfurized polyacrylonitrile for high-performance lithium sulfur batteries: advances and prospects

Lithium sulfur (Li–S) batteries have a high theoretical specific capacity (1675 mA h g−1) and energy density (2600 W h kg−1), possessing high potential as next-generation rechargeable batteries for long-distance transportation and large grid applications. Sulfurized polyacrylonitrile (SPAN) is known as an alternative sulfur cathode material for practical application in Li–S batteries, because of its capability of completely eradicating the shuttle of lithium polysulfides in comparison with elemental sulfur cathodes. It can be synthesized by simply heating polyacrylonitrile (PAN) and sulfur powder under the protection of an inert atmosphere and has good compatibility with carbonate-based electrolytes that are commonly used in Li-ion batteries, as well as adaptability to the manufacturing processes of current lithium-ion (Li-ion) batteries. In the past few decades, SPAN has been widely investigated with respect to its chemical structure, redox reaction and electrochemical performance. Thus, it is of great interest to thoroughly summarize the recent progress in engineering SPAN material for practical application in Li–S batteries. This review aims to describe the achievements in this promising material and gives a comprehensive overview in terms of structures, mechanisms and performances. The relationship between the cell performance between the strategies applied and the cell performance was statistically analyzed on the basis of metadata from the literature, which could give the research direction and clues for the further study. Challenges and possible directions are also discussed to shed light on its implementation in large-scale commercial production in the future.