2D Sandwich-Like α-Zirconium Phosphate/Polypyrrole: Moderate Catalytic Activity and True Sulfur Confinement for High-Performance Lithium–Sulfur Batteries

Although lithium–sulfur batteries are promising environmentally friendly and low-cost energy storage devices with high energy densities, many obstacles such as poor conductivity, volume expansion and the “shuttle effect” still limit their large-scale commercialization. In this work, a 2D sandwich-like α-ZrP/polypyrrole (α-ZrP/PPy) material with a nanosheet structure was designed as a sulfur host. The material can provide unique ion transfer channels for the rapid transfer of Li + ions and catalytically promote the conversion of lithium polysulfides (LiPSs). Moreover, the α-ZrP nanosheets provides a true covalent anchor for sulfur species, whereas the PPy builds a physical barrier and forms a conductive network for accelerating the electron transport and promoting the electrochemical performance. In addition, the moderate catalytic activity and true sulfur confinement effect of α-ZrP were confirmed by experiments and theoretical calculations. The α-ZrP/PPy@S cathode exhibits a highly reversible capacity of 727.2 mAh g −1 even at a high current density of 5 C, offering a novel cathode material for high performance Li–S batteries. Graphical Welcome to the cell : 2D sandwich-like α-ZrP/polypyrrole (α-ZrP/PPy) nanosheets are designed as a sulfur host material. The material has a remarkably enhanced cycling performance, excellent rate capability, and improved coulombic efficiency owing to the true covalent confinement of sulfur and moderate catalytic activity for the conversion of LiPSs. Such α-ZrP/PPy@S composites can be applied as promising cathode materials for Li–S batteries.