Mxene/SnO2 QDs Heterostructure Based Separator Interlayer Enable Kinetically Boosted Lithium-Sulfur Batteries

Abstract

Lithium-sulfur (Li-S) batteries have drawn much attention as potential next-generation energy storage technology. However, their practical implementation faces challenges related to the cathode and anode, including the sluggish reactions, shuttle effect and lithium dendrite growth. The design of an efficient separator interlayer has been proved to be effective in mitigating the lithium polysulfides (LiPSs) shuttling and suppressing the formation of lithium dendrites. Here, we report a novel ultrathin and laminar MXene/SnO2 quantum dots based Mott-Schottky heterostructure with abundant active sites at their hetero-boundaries as a separator interlayer. Such design combines highly polar SnO2, conductive MXene, and highly active heterojunctions, synergistically enabling strong anchoring of LiPSs, rapid electron transportation and efficient LiPSs catalytic conversion (See figure 1). Moreover, the interlayer exhibits excellent performance at the anode side by suppressing lithium dendrite growth due to its high Young's modulus. As a consequence, the incorporation of this ultrathin and weight-negligible separator interlayer has resulted in a significant capacity enhancement of at least 20 %. In addition, we achieved an area capacity exceeding 6 mAh/cm2 at a high sulfur loading of 7.5 mg/cm2 during cycling. These findings pave new ways for further advancements in Li-S batteries and highlight the potential of heterostructure catalysis for high-performance energy storage applications. Figure 1