Novel 2D bifunctional layered rare-earth hydroxides@GO catalyst as a functional interlayer for improved liquid-solid conversion of polysulfides in lithium-sulfur batteries

The detrimental “shuttle effect” of lithium polysulfides (LiPSs) together with sluggish multi-order reaction kinetics are the main drawbacks hindering lithium-sulfur (Li-S) batteries from commercial success. Here, we first propose the implementability of layered rare-earth hydroxides (LREHs) in Li-S batteries to optimize electrochemical performance. In this work, a two-dimensional (2D) rare-earth-based composite constructed by the layered gadolinium hydroxy chloride [Gd2(OH)5(H2O)n]Cl nanoplates (LGdH NPs) and graphene oxide (GO) was designed as a sulfur immobilizer for Li-S batteries. Combining the experimental results and density functional theory (DFT) calculations, it's revealed that the LGdH@GO composite not only provides a strong anchoring of the intermediates during cycling, but also acts as an effective catalyst to accelerate the liquid-solid conversion of polysulfides. The Li-S batteries assembled by LGdH@GO modified separators delivered a superior rate performance with a specific capacity of 605.34 mAh/g at 5 C, as well as excellent cycle stability with a decay rate of 0.087% over 500 cycles at 2 C. This study provided a deep understanding of the mechanism to suppress the “shuttle effect” by the LREHs, and a guide to design effective functional interlayers for high-performance Li-S batteries with excellent electrocatalytic activity.