Aluminum ion batteries (AIBs) are deemed an encouraging prospect for energy storage applications owing to their beneficial attributes, including considerable theoretical specific capacity, heightened safety measures, affordability, and plentiful availability of materials. However, the inherent characteristics of cathode materials have greatly limited the further development of AIBs. In this work, SnS₂@CNFs composites were prepared via a combination of hydrothermal and electrospinning strategy. Specifically, SnS₂ nanosheets, resembling flakes in their two-dimensional form, uniformly coated on the carbon fibers, forming a three-dimensional interconnected network seamlessly integrated with the continuous carbon substrate. This structure is conducive to shortening the ion transmission path, ensuring sufficient electrolyte contact, and facilitating electron transfer and transfer at the phase interfaces. As a self-supporting electrode for AIBs, the SnS₂@CNFs electrode exhibited remarkable cyclability, retaining a residual capacity of approximately 70 mA h g⁻¹ with a Coulombic efficiency close to 97 % after 500 cycles at 100 mA g⁻¹. The good cycle stability originates from the flexible carbon substrate effectively alleviating the volume expansion phenomenon caused by ion deintercalation in SnS₂. In addition, first-principles calculations show that the substitution behavior of aluminum atoms in SnS₂ crystals exhibits obvious selectivity, but exceeding the energy threshold of conventional substitution reactions indicates that reactions are unlikely to occur. By constructing models to explore the embedding path of aluminum ions in SnS₂ crystals, the results showed that the embedding behavior mainly occurs in the van der Waals gap interstitial rather than within the crystal monolayer, and the sulfur atom top position is used as the optimal embedding site.

中文翻译：

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用于高性能锂离子电池的具有 3D 结构的分层 SnS2@CNFs 复合材料：通过第一性原理计算揭示 Al3+ 脱嵌机制

铝离子电池 （AIB） 被认为是储能应用令人鼓舞的前景，因为它们具有有益的属性，包括相当大的理论比容量、增强的安全措施、可负担性和丰富的材料可用性。然而，正极材料的固有特性极大地限制了 AIB 的进一步发展。在这项工作中，通过水热和静电纺丝策略相结合制备了 SnS ₂ @CNFs 复合材料。具体来说，类似于二维形式的薄片的 SnS ₂ 纳米片均匀地涂布在碳纤维上，形成一个与连续碳基材无缝集成的三维互连网络。这种结构有利于缩短离子传输路径，保证电解质充分接触，促进电子转移和相界面转移。作为 AIB 的自支撑电极，SnS ₂ @CNFs 电极表现出卓越的可循环性，在 100 mA g ⁻¹ 下循环 500 次后，仍保留约 70 mA h g ⁻¹ 的剩余容量，库仑效率接近 97%。良好的循环稳定性源于柔性碳衬底，有效缓解了 SnS ₂ 中离子脱嵌引起的体积膨胀现象。此外，第一性原理计算表明，铝原子在 SnS ₂ 晶体中的取代行为表现出明显的选择性，但超过常规取代反应的能量阈值表明反应不太可能发生。 通过构建模型探究铝离子在 SnS ₂ 晶体中的嵌入路径，结果表明，嵌入行为主要发生在范德华间隙间隙中，而不是发生在晶体单层内部，以硫原子顶部位置为最佳嵌入位点。