Referred to as potential options for anodes in sodium-ion batteries, transition metal chalcogenides (TMCs) exhibit unique electronic and structural characteristics. However, the limited electrical conductivity inherent in them poses a hindrance to electron transport, while their tendency to undergo volumetric expansion during cycling exacerbates structural instability, thereby imposing constraints on practical applications. Herein, a dual molten salt etching strategy followed by a sulfidation-selenidation process was employed to anchor multi-component sulfides FeS2/NiS and FeSe/NiSe onto conductive Ti3C2Tx MXene, achieving superior sodium storage performance. Owing to the enhanced Na⁺ and faster kinetics of electronic transport, mechanical strain is effectively reduced, and strong covalent interactions are formed at the interface, significant enhancement in the cycling stability is observed for the anodes of Ti3C2Tx@FeS2/NiS and Ti3C2Tx@FeSe/NiSe (with specific capacities of 309.4 and 162.6 mAh g−1, respectively, after 1000 cycles at 5 A g−1, with a former retention capacity rate that can reach as high as 87.8 %) and exceptional rate performance (252.1 and 207.8 mAh g−1, respectively, at 8 A g−1). Furthermore, full cells assembled by pairing Ti3C2Tx@FeS2/NiS and Ti3C2Tx@FeSe/NiSe with Na3V2(PO4)3 cathodes also demonstrate excellent cycling performance, with both configurations achieving up to 500 cycles. The suggested approach enables efficient utilization of byproducts from Lewis acidic etching, expanding possibilities for synthesizing high-performance anodes in sodium-ion batteries consisting of MXene and TMCs.

中文翻译：

---

通过双熔盐刻蚀增强 MXene 过渡金属硫属化物阳极中的钠存储


过渡金属硫系物 （TMC） 被称为钠离子电池负极的潜在选择，表现出独特的电子和结构特性。然而，它们固有的有限导电性阻碍了电子传输，而它们在循环过程中发生体积膨胀的趋势加剧了结构的不稳定性，从而对实际应用造成了限制。本文采用双熔盐蚀刻策略，然后进行硫化-硒化工艺，将多组分硫化物 FeS2/NiS 和 FeSe/NiSe 锚定在导电 Ti3C2Tx MXene 上，实现卓越的储钠性能。由于增强的 Na⁺ 和更快的电子传输动力学，机械应变被有效降低，并在界面处形成强烈的共价相互作用，观察到 Ti3C2Tx@FeS2/NiS 和 Ti3C2Tx@FeSe/NiS 的阳极（比容量分别为 309.4 和 162.6 mAh g-1，在 5 A g-1 下循环 1000 次后，循环稳定性显着增强， 具有高达 87.8% 的保留容量率和出色的倍率性能（在 8 A g-1 时分别为 252.1 和 207.8 mAh g-1）。此外，通过将 Ti3C2Tx@FeS2/NiS 和 Ti3C2Tx@FeSe/NiSe 与 Na3V2（PO4）3 阴极配对组装的全电池也表现出出色的循环性能，两种配置都实现了高达 500 次循环。所建议的方法能够有效利用 Lewis 酸性蚀刻的副产物，扩大了在由 MXene 和 TMC 组成的钠离子电池中合成高性能阳极的可能性。