Abstract：
CuS have received widespread attention for application as anode materials in sodium-ion batteries due to their potent capabilities and eco-friendly properties. However, it is a challenge to achieve a high rate capability and long cycle stability owing to the heterogeneous transfer of sodium ions during charge-discharge, the interior poor electron conductivity and repeated volumetric expansion of copper sulfide. In this study, Sb-doped CuS hollow nanocubes coated with carbon shells (Sb-CuS@C) was designed and constructed as anode nanomaterials in sodium ion batteries. Thanks to the intrinsic good electron conductivity and chemical stability of carbon shells, Sb-CuS@C possesses a higher overall electron transfer as anode material, avoids agglomeration and structural destruction during the cycling. As a result, the synthesized Sb-CuS@C achieved an excellent reversible capacity of 595 mA h g-1 after 100 cycles at 0.5 A g-1 and a good rate capability of 340 mA h g-1 at a higher 10 A g-1. DFT calculations clarify that the uniformly doped Sb would act as active sodiophilic nucleation sites to help adsorbing Na+ during discharging and leading uniform sodium deposition. This work provides a new insight into the structural and componential modification for common transition-metal sulfides towards application as anode materials in SIB.
摘要：
CuS由于其强大的功能和环保特性，在钠离子电池中作为负极材料的应用受到了广泛的关注。然而,由于在充放电过程中钠离子的非均相转移，实现高倍率性能和长循环稳定性是一个挑战，硫化铜的内部导电性差和重复的体积膨胀。在这项研究中,设计并构建了掺Sb碳壳包覆的CuS中空纳米立方体(Sb-CuS@C)作为钠离子电池的负极纳米材料。由于碳壳固有的良好电子传导性和化学稳定性，Sb-CuS@C作为阳极材料具有较高的整体电子转移，避免了循环过程中的团聚和结构破坏。因此,在0.5Ag-1下进行100次循环后，合成的Sb-CuS@C实现了595mAhg-1的出色可逆容量，在较高的10Ag-1下具有340mAhg-1的良好倍率性能。DFT计算表明，均匀掺杂的Sb将充当活性亲钠成核位点，以帮助在放电过程中吸附Na并导致均匀的钠沉积。这项工作为常见的过渡金属硫化物在SIB中用作阳极材料的结构和成分改性提供了新的见解。
