Macroscopic built-in polarization electric field powers high lithium-ion transport for all-solid-state lithium-sulfur batteries

Abstract

Traditional liquid lithium-sulfur batteries possess the merits of high energy density and low cost, and have a wide application prospect in the field of energy storage; however, the growth of lithium dendrites, the side reaction of the liquid electrolyte, and the harmful “shuttle effect” of lithium polysulfides have hindered their practical application. Herein, a solid-state composite polymeric electrolyte with a macroscopic built-in polarization electric field is designed to improve lithium-ion transport and depress shuttle effect. The introduction of barium titanate as a functional filler effectively reduces the crystallinity of the polymer and promotes the dissociation of the lithium salt. At the same time, the built-in polarization electric field generated by its crystal structure provides a strong driving force for lithium-ion transport, thus accelerating lithium-ion migration. The experimental results show that the built-in electric field can enhance the lithium-ion transport and accelerate redox kinetics. Furthermore, the macroscopic charges can establish strong chemical interactions between polysulfides, which leads to the suppression of the shuttle effect and effectively improves the cycling stability of all-solid-state lithium-sulfur batteries. Benefiting from these properties, Li||Li symmetric batteries exhibit stable cycling for more than 900 h, and all-solid-state lithium-sulfur batteries have a high cycling stability of more than 200 cycles at a rate of 0.1 C. This work provides a simple and effective method for designing high-performance all-solid-state lithium-sulfur batteries.