In Situ Anchoring Ultrafine ZnS Nanodots on 2D MXene Nanosheets for Accelerating Polysulfide Redox and Regulating Li Plating

Abstract

Lithium−sulfur (Li−S) battery is a promising energy storage system due to its cost effectiveness and high energy density. However, formation of Li dendrites from Li metal anode and shuttle effect of lithium polysulfides (LiPSs) from S cathode impede its practical application. Herein, ultrafine ZnS nanodots are uniformly grown on 2D MXene nanosheets by a low‐temperature (60 °C) hydrothermal method for the first time. Distinctively, the ZnS nanodot‐decorated MXene nanosheets (ZnS/MXene) can be easily filtered to be a flexible and freestanding film in several minutes. The ZnS/MXene film can be used as a current collector for Li‐metal anode to promote uniform Li deposition due to the superior lithiophilicity of ZnS nanodots. ZnS/MXene powders obtained by freeze drying can be used as separator decorator to address the shuttle effect of LiPSs due to their excellent adsorbability. Theoretical calculation proves that the existence of ZnS nanodots on MXene can obviously improve the adsorption ability of ZnS/MXene with Li+ and LiPSs. Li−S full cells with composite Li‐metal anode and modified separator exhibit remarkable rate and cycling performance. Other transition metal sulfides (CdS, CuS, etc.) can be also grown on 2D MXene nanosheets by the low‐temperature hydrothermal strategy.

Hollow Structure Co1–xS/3D-Ti3C2Tx MXene Composite for Separator Modification of Lithium–Sulfur Batteries

“…The formation of insulating layers of solid Li 2 S 2 /Li 2 S 2 at the interface between the positive electrode and the separator hinders Li + diffusion . Owing to the high adsorption affinity, abundant active sites, and unique multilevel hierarchical conductive network structure, the Co 1– x S/3D-Ti 3 C 2 T x modification layer on the positive side of the separator accelerates the oxidation and reduction process of insulating Li 2 S 2 /Li 2 S 2 . Therefore, the battery using the Co 1– x S/3D-Ti 3 C 2 T x -modified separator exhibits excellent Li + diffusion behavior.…”

In Situ Growth Engineering on 2D MXenes for Next‐Generation Rechargeable Batteries

“…Recently, our group achieved the in situ growth of ultrafine ZnS nanodots on 2D MXene nanosheets (ZnS/MXene) by a low-temperature (60 °C) hydrothermal method (Figure 14a-d). [141] The low-temperature fabrication process could prevent the oxidation of MXene. The ZnS/MXene can be processed to be flexible and freestanding films by vacuum filtration.…”

“…As a result, MXene can be easily oxidized by H 2 O or residual O 2 in water at high temperature during the hydrothermal process, which limits their widespread application. In fact, [141] Copyright 2023, Wiley-VCH. 1059 mAh g À1 after 100 cycles at 0.5C [140] the oxidation issue can be effectively relieved by reasonably lowing the hydrothermal temperature, removing residual O 2 in water solvent, or adding antioxidants.…”

“…d) High-resolution transmission electron microscope image of ZnS/MXene. Reproduced with permission [141]. Copyright 2023, Wiley-VCH.…”

Recent Progress on Natural Clay Minerals for Lithium‐Sulfur Batteries

“…[33] Additionally, the "polysulfide shuttling" and selfdischarge phenomenon occur between the anode and the cathode, participating in the oxidation reactions at the cathode and reduction reactions with lithium. [34] To overcome these drawbacks, various strategies based on the natural clay minerals have been proposed, such as using clay minerals as sulfur carriers, constructing heterostructures, or using them as template materials in the cathode of LiÀ S batteries.…”