Ultrathin 2D-2D MXene-LDH Interlayer with High Polysulfide Adsorption Ability for Advanced Li-S Batteries.

Lithium-sulfur (Li-S) batteries are considered as promising energy storage systems due to the high energy density of 2600 W h kg. However, the practical application of Li-S batteries is hindered by the inadequate conductivity of sulfur and LiS, as well as the shuttle effect caused by polysulfides during the charge-discharge process. Introducing a conductive interlayer between the cathode and the separator to physically resist polysulfides represents an effective and straightforward approach to mitigate the shuttle effect in Li-S batteries. In this paper, an ultrathin (<1 μm) 2D-2D MXene-LDH interlayer with high polysulfide adsorption ability was introduced to Li-S batteries. The synergistic effect between MXene and layered double hydroxide greatly improved the adsorption effect of the interlayers: the conductive TiCT MXene chemically adsorbs polysulfides and promotes their fast transfer, and the NiCo-LDH alleviates the restack of MXene and facilitates Li diffusion. After inserting the MXene-LDH interlayer, the Li-S batteries exhibit an enhanced specific capacity of 1137.6 mA h g at 0.1 C and retain 622.6 mA h g after 100 cycles. The ultrathin 2D-2D interlayer offers a feasible way for the development of highly efficient and lightweight interlayers in Li-S batteries.