The 2H-MoS₂ incorporated with N-doped carbon (2H-MoS₂/NC) with high discharge capacity has attracted more research focus as an anode material for K-ion batteries (PIBs). However, large longitudinal lattice deformation at 2H-MoS₂/NC heterointerfaces caused by interfacial intercalation of K ions negatively impacts the structural stability, which limits its cycling performance. In this paper, interfacial engineering has been applied to optimize the structural stability of 2H-MoS₂/NC. By using first-principle simulation, the evolutions of longitudinal lattice deformation, K adsorption/diffusion performance/behaviour, interfacial strength, and electronic property with the interfacial interlayer spacing have been systematically explored. The results show that with the increase of interlayer spacing from 5.0 to 7.0 Å, the lattice deformation, interfacial strength, and K adsorption kinetics first decrease sharply with interlayer spacing in the range of 5.0–6.5 Å, and then they drop minorly at 6.5–7.0 Å. The K interfacial diffusion capability can be improved due to the decreased charge accumulation at interface that leads to weakened K–S bonding with a rising interlayer spacing. Based on variation of structural stability and K storage performance, an optimal interlayer spacing of 6.75 Å is confirmed. These findings can provide a solid theoretical basis and guidance for the experimental preparation of high-performance 2H-MoS₂/NC electrode materials and further cultivate new concepts for the optimal design of two-dimensional composite electrode materials.

Graphical Abstract

中文翻译：

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用于快速钾界面储存的2H-MoS2/N掺杂碳复合材料的界面工程

具有高放电容量的掺氮碳的2H-MoS _{2 (2H-MoS 2} /NC)作为钾离子电池(PIB)的负极材料吸引了更多的研究热点。然而，K离子界面插入引起的2H-MoS ₂ /NC异质界面的大纵向晶格变形会对结构稳定性产生负面影响，从而限制了其循环性能。在本文中，应用界面工程来优化2H-MoS ₂ /NC的结构稳定性。通过第一性原理模拟，系统地探讨了纵向晶格变形、K吸附/扩散性能/行为、界面强度和电子性能随界面层间距的变化。结果表明，随着层间距从 5.0 增加到 7.0 Å，晶格变形、界面强度和 K 吸附动力学首先在层间距为 5.0-6.5 Å 范围内急剧下降，然后在 6.5 Å 范围内小幅下降。 7.0 埃。由于界面电荷积累减少，导致 K-S 键合减弱，层间距增大，因此 K 界面扩散能力得到改善。基于结构稳定性和储钾性能的变化，确定了最佳层间距为 6.75 Å。这些研究结果可为高性能2H-MoS ₂ /NC电极材料的实验制备提供坚实的理论基础和指导，并进一步为二维复合电极材料的优化设计培育新理念。

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