Overview of the Latest Developments and Perspectives about Noncarbon Sulfur Host Materials for High Performance Lithium–Sulfur Batteries

Lithium–sulfur (Li–S) batteries have attracted great attention in environmentally and friendly energy storage systems due to their excellent theoretical specific capacities and high energy densities. In addition, the element sulfur has a wide range of raw materials and low production costs and is considered to be a material with the most development potential. However, the poor electrical conductivity of sulfur, the volume expansion of sulfur during polarization, and the shuttle effect of lithium polysulfides (LiPSs) severely hinder the commercialization of Li–S batteries. Since carbon materials containing light nonpolar or weakly polar substances are used as sulfur hosts, there will be some difficulties in cycling stability, and the volumetric energy densities of Li–S batteries will be destroyed. In order to solve the existing problems, some polar substances are introduced into the cathode material to improve the cycle stability and effectively suppress the shuttle effect. This review presents polar materials commonly used in Li–S batteries, including single metals, metal nitrides, metal oxides, metal sulfides, and conducting polymers. Finally, this review not only summarizes the research directions and challenges of polar material applications but also looks forward to the development prospects of batteries, provides a pathway for the practical application of noncarbon sulfur host materials in Li–S batteries, and inspires more researchers to work on cathode materials.