Key Laboratory for Soft Chemistry and Functional Materials, Ministry of Education, Nanjing University of Science and Technology , Nanjing 210094, China.
School of Materials Science and Engineering, Nanyang Technological University , Singapore 639798.
ACS Nano. 2017 Oct 24;11(10):10599-10607. doi: 10.1021/acsnano.7b06133. Epub 2017 Sep 27.
Transition metal (M = Fe, Co, Ni) and Se codoped two-dimensional uniform NbS (MNbSSe) nanosheets were synthesized via a facile oil-phase synthetic process. The morphology of MNbSSe can be adjusted by tuning the amount of metal and Se introduced into NbS. Among them, the optimized FeNbSSe nanosheets, with lateral sizes of 1-2 μm and approximately 5 nm thick, achieve the best Li-ion and Na-ion storage properties. For example, the FeNbSSe nanosheets depict excellent rate capabilities with fifth-cycle specific capacities of 461.3 mAh g at 10 A g for Li storage and 136 mAh g at 5 A g for Na storage. More significantly, ultralong cyclic stabilities were achieved with reversible specific capacities of 444 mAh g at 5 A g during the 3000th cycle for Li storage and 250 mAh g at 1 A g during the 750th cycle for Na storage. Post-treatment high-resolution transmission electron microscopy was studied to prove that the reversible Li-ion storage in NbS was based on a conversion reaction mechanism.
过渡金属（M=Fe、Co、Ni）和 Se 共掺杂二维均匀 NbS（MNbSSe）纳米片通过简便的油相合成工艺合成。通过调节引入 NbS 的金属和 Se 的量可以调整 MNbSSe 的形态。其中，优化的 FeNbSSe 纳米片，具有 1-2μm 的横向尺寸和约 5nm 的厚度，实现了最佳的锂离子和钠离子存储性能。例如，FeNbSSe 纳米片在锂存储时，在 10A g 的第五个循环中具有 461.3mAh g 的优异倍率性能，在钠存储时，在 5A g 的第五个循环中具有 136mAh g 的优异倍率性能。更重要的是，在 3000 次循环中，在 5A g 的条件下，可逆比容量为 444mAh g，在 750 次循环中，在 1A g 的条件下，可逆比容量为 250mAh g，实现了超长的循环稳定性。进行了后处理高分辨率透射电子显微镜研究以证明 NbS 中的可逆锂离子存储基于转换反应机制。
