Cathode Materials for Lithium Sulfur Batteries: Design, Synthesis, and Electrochemical Performance

With the rapid development of electronic devices, portable electronics, and electric vehicles, the energy density and cycle life of LIBs are insufficient for the demands. Based on the reaction mechanisms, lithium-sulfur (Li-S) batteries have a high specific capacity of 1672 mAh/g, with a theoretical energy density up to 2600 Wh/Kg. However, the sulfur cannot serve as cathode individually because of its isolation nature and soluble compounds, which necessitates a second component as a conducting matrix and sulfur host. Thus, sulfur cathodes have diversified through microstructure designing with various materials, including inorganic compounds, polymers, carbon materials, and their hybrids, which should be satisfied several essential requirements, such as high stable incorporation with sulfur, high electrical conductivity of electrode materials, and loose framework to suffer the volume expansion of cathode during charge-discharge process. These investigations may provide the effective routes to prepare different new cathode materials with unique structures and morphologies for Li-S batteries, which improve cycling stability, coulombic efficiency, and rate capacity of the electrode at higher current density.