A Three-Region Configuration for Enhanced Electrochemical Kinetics and High-Areal Capacity Lithium-Sulfur Batteries

A main hurdle for the commercial application of lithium-sulfur (Li-S) batteries lies in inadequate loading of sulfur due to a huge volume change over charging-discharging, poor electric conductivity of sulfur and associated sulfides, and the shuttling effect of lithium polysulfides (LiPS). Herein, a universal three-region configuration including: Region I (sulfur source region), Region II (LiPS electrocatalysis region), and Region III (multi-functional shield) for high-areal capacity Li-S batteries is proposed. Mechanism of the configuration including the competitive relationship between Region II and Region III based on the Sabatier principle is further confirmed through density functional theory theoretical simulation and a series of in situ experimental methods. Compared with a conventional mechanical mixing electrode structure, it is demonstrated that the orderly integration three-region configuration is able to prevent shuttling of LiPS effectively, which delivers high gravimetric energy density at the sulfur loading of 10.7 mg cm(-2). Furthermore, a pouch cell achieves a high capacity of 148.15 mAh at a sulfur loading of 108 mg, which is by far higher than that of most previous batteries and pouch Li-S cells. Impressively, with bending and even partial damage, the pouch cell can still work normally, showing considerable safety.

Automated summary

This article introduces a three-region configuration for high-capacity Li-S batteries and explains its mechanism through experiments and theoretical simulations. Compared with traditional structures, this configuration can effectively prevent the shuttling of LiPS and achieve higher energy density and capacity. In addition, the pouch cell also demonstrates high safety and reliability, even under bending or partial damage.