The recent research progress and prospect of gel polymer electrolytes in lithium-sulfur batteries

Lithium sulfur (Li-S) battery is one of the most promising energy storage battery systems on account of outstanding special capacity and high energy density. However, traditional liquid electrolytes bring about unsatisfactory growth of lithium dendrite and safety problems due to its leak and low boiling point. Gel polymer electrolytes (GPEs) are intermediate between liquid electrolytes and solid electrolytes, which can be acted as not only electrolyte but also separator, which reduce leakage of liquid electrolytes and high interface resistance of solid electrolytes. In this review, an extensive generalization about the preparation methods such as solution casting, phase inversion, in-situ polymerization strategy, UV curing and electrospinning producing various GPEs, and different matrix of GPEs in Li-S batteries are presented. For Li-S batteries, modifying diverse substrates such as PEO, PVDF, PVDF-HFP, PMMA, cross-linked polymers and PMIA, mainly ameliorates the most severe “shuttle effects” of polysulfides and hinder the growth of lithium dendrites. Specially, two mechanisms (physical barrier and chemical adsorption) inhibiting polysulfides shuttle are described in detail. Finally, we conclude with an outlook section to provide some insights on the future prospects of GPEs in Li-S batteries. This discussion and proposed strategies will offer more avenues to the practical application Li-S batteries with high electrochemical performance in the future.