Modulating Ion‐Dipole and Dipole–Dipole Interactions for Stable Wide‐Temperature‐Range Lithium–Sulfur Batteries Enabled by Quantum‐Dot Catalysts

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Angewandte Chemie Int Ed, Wiley-VCH

Content

Angewandte Chemie International Edition, EarlyView.

The electrochemical inertness of Li2S2 leads to irreversible sulfur loss. MoNQDs/NC reconfigure the solvation shell structure, thereby weakening the ion‐dipole effect within Li(solvent)x+ and enabling a fast desolvation process. Furthermore, localized dipole fields from their ordered Mo–N atoms enhance dipole–dipole interactions with Li2S2. This induces tensile strain, destabilizing Li2S2 and promoting its decomposition. Via this dual mechanism, MoNQDs/NC enable high‐sulfur‐loading LSBs to achieve low capacity decay over a wide temperature range. Abstract The incomplete conversion of sulfur species, particularly the pivotal intermediate solid Li2S2 during redox processes, poses a significant limitation on the cyclability of lithium–sulfur batteries (LSBs). Herein, a synergistic modulation strategy of ion‐/dipole–dipole interactions that tailors the solvation sheath configuration and activates the electrochemical reactivity of Li2S2 is initially proposed for accelerating kinetics. As a proof of concept, the molybdenum nitride quantum dots located on nitrogen‐doped carbon (MoNQDs/NC) were designed. Advanced in situ/ex situ characterizations combined with theoretical calculations reveal that MoNQDs/NC effectively weaken the ion‐dipole interactions within Li(solvent)x+ species, thereby facilitating the desolvation process. Furthermore, the robust dipole–dipole interactions between polar domains of MoNQDs and Li2S2 are realized to generate localized tensile strain fields to destabilize the S─S/Li─S bonds network. Consequently, the optimal cells maintain a high areal capacity (>5.0 mAh cm−2) after 50 cycles at high sulfur loading (4.4–9.1 mg cm−2) over a wide temperature range (0–60 °C). Furthermore, the pouch cell with a sulfur loading of 1.5 g retained a capacity of 1.79 Ah after 15 cycles, highlighting the potential of this ion‐dipole modulation strategy for commercializing LSBs.

The electrochemical inertness of Li₂S₂ leads to irreversible sulfur loss. MoNQDs/NC reconfigure the solvation shell structure, thereby weakening the ion-dipole effect within Li(solvent) _x ⁺ and enabling a fast desolvation process. Furthermore, localized dipole fields from their ordered Mo–N atoms enhance dipole–dipole interactions with Li₂S₂. This induces tensile strain, destabilizing Li₂S₂ and promoting its decomposition. Via this dual mechanism, MoNQDs/NC enable high-sulfur-loading LSBs to achieve low capacity decay over a wide temperature range.

Abstract

The incomplete conversion of sulfur species, particularly the pivotal intermediate solid Li₂S₂ during redox processes, poses a significant limitation on the cyclability of lithium–sulfur batteries (LSBs). Herein, a synergistic modulation strategy of ion-/dipole–dipole interactions that tailors the solvation sheath configuration and activates the electrochemical reactivity of Li₂S₂ is initially proposed for accelerating kinetics. As a proof of concept, the molybdenum nitride quantum dots located on nitrogen-doped carbon (MoNQDs/NC) were designed. Advanced in situ/ex situ characterizations combined with theoretical calculations reveal that MoNQDs/NC effectively weaken the ion-dipole interactions within Li(solvent) _x ⁺ species, thereby facilitating the desolvation process. Furthermore, the robust dipole–dipole interactions between polar domains of MoNQDs and Li₂S₂ are realized to generate localized tensile strain fields to destabilize the S─S/Li─S bonds network. Consequently, the optimal cells maintain a high areal capacity (>5.0 mAh cm⁻²) after 50 cycles at high sulfur loading (4.4–9.1 mg cm⁻²) over a wide temperature range (0–60 °C). Furthermore, the pouch cell with a sulfur loading of 1.5 g retained a capacity of 1.79 Ah after 15 cycles, highlighting the potential of this ion-dipole modulation strategy for commercializing LSBs.

Yongqian He, Duanfeng Xiong, Manfang Chen, Wanqi Zhang, Sisi Liu, Yongjie Ye, Mengqing Wang, Ying Chen, Qin Tang, Xuewen Peng, Caixiang Wang, Hongyang Zhan, Hong Liu, Min Liu, Jincang Su, Hongbo Shu, Jian Wang, Xianyou Wang

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