还原氧化石墨烯包覆MOF衍生In_(2)Se_(3)用于钠离子电池负极

RGO-Coated MOF-Derived In_(2)Se_(3) as a High-Performance Anode for Sodium-Ion Batteries

MOF衍生金属硒化物由于其有序的碳骨架结构和高导电性,被认为是钠离子电池极具前景的负极材料。它们具有快速的电子/离子输运通道,有利于钠离子的嵌入和脱出。然而,循环过程中的大量体积膨胀会导致结构坍塌。为了解决这个问题,通过表面改性在MOF衍生金属硒化物表面引入了一个二维的还原氧化石墨烯网络,既可以缓解体积变化,又能加速电子转移。实验证实这种策略是有效的,在1 A·g^(-1)下500次循环后,包覆了还原氧化石墨烯的复合材料电极容量保持率提高到了95.2%。相比之下,不含还原氧化石墨烯的容量保留率仅为74.2%。此外,由于还原氧化石墨烯网络和MOF衍生In_(2)Se_(3)协同作用,在0.1 A·g^(-1)下显示出了468 m Ah·g^(-1)的优越容量。而在相同的电流密度下,未包覆还原氧化石墨烯的只产生393 m Ah·g^(-1)的比容量。采用循环伏安法(CV)研究了In_(2)Se_(3)@C/rGO电极的电化学过程,结果表明其具有良好的电化学反应活性。此外,还通过原位X射线衍射探索了In_(2)Se_(3)的转换-合金化双重储钠机制,揭示了其高比容量产生的来源。本研究有望为还原氧化石墨烯优化MOF衍生物作为钠离子电池负极材料提供参考。

MOF-derived metal selenides are promising candidates as effective anode materials in sodium-ion batteries(SIBs) owing to their ordered carbon skeleton structure and the high conductivity of selenides. They can be imparted with rapid electron/ion transport channels for the insertion/de-insertion of Na+. In this study, MOF-derived In_(2)Se_(3)was prepared as an anode material for SIBs. However, the large volume expansion during cycling leads to structural collapse, which affects the charging and discharging circulation life of the battery. To address this, a two-dimensional rGO network was introduced on the MOF-derived In_(2)Se_(3)surface by surface modification. Field-emission scanning electron microscopy(FE-SEM) and X-ray photoelectron spectroscopy(XPS) results confirmed the successful synthesis of the In_(2)Se_(3)@C/rGO composite. The structures with two types of carbon enhanced the charge transfer kinetics and provided two stress-buffering layers. Thus, the volume change could be accommodated and simultaneously, electron transfer was accelerated. This technique was effective, as proved by the enhanced capacity retention of 95.2% at 1 A·g^(-1)after 500 cycles. In contrast, the capacity retention of the MOF-derived material without r GO was only 74.2%. Additionally, due to the synergistic effect of the r GO network and the MOF-derived In_(2)Se_(3), the anode showed a superior capacity of 468 m Ah·g^(-1)at 0.1 A·g^(-1). Conversely, at the same current density, the uncoated material delivered only a capacity of 393 m Ah·g^(-1). To study the electrochemical process of the electrode, the In_(2)Se_(3)@C/rGO electrode was subjected to cyclic voltammetry(CV) measurements;the results showed that the In_(2)Se_(3)@C/rGO electrode had notable electrochemical reactivity. In addition, in situ X-ray diffraction(XRD) was performed to explore the sodium storage mechanism of In_(2)Se_(3), demonstrating that In_(2)Se_(3)had a dual Na+storage mechanism involving conversion and alloying reactions, and revealing the origin of its high theoretical specific capacity. This study is expected to serve as a reference for preparing optimized r GO-based materials for use as SIB anodes.