Design of PVDF–g–PAA Binder Endowing High Sulfur Loading With Enhanced Performance of Lithium–Sulfur Batteries

Abstract

Lithium–sulfur (Li–S) batteries have received considerable attention as promising candidates for next-generation batteries because of their high theoretical energy density (≈2600 Wh kg⁻¹). However, despite their abundant active material and high theoretical capacity, the commercialization of Li–S batteries has been hindered by several difficulties such as the shuttle effect of lithium polysulfides (LiPS). In this study, we designed poly (vinylidene fluoride)–graft–poly (acrylic acid) (PVDF–g–PAA) as a novel binder to realize high sulfur loading electrodes for Li–S batteries. The synthesis conditions of PVDF–g–PAA were controlled based on its chemical structure, mechanical properties, and electrochemical performance. The optimal structure of PVDF–g–PAA exhibited high LiPS adsorption ability compared to that of PVDF, which retained its mechanical properties. Therefore, the unit cell with a high sulfur loading of 5.7 mg cm⁻² fabricated using PVDF–g–PAA yielded a high reversible capacity of 644.1 mAh g⁻¹ after 100 cycles. Consequently, this study provides a useful approach to improve the cycling performance of Li–S batteries by modifying commercial binders, which demonstrates their practical potential for developing Li–S batteries.