National & Local United Engineering Laboratory for Power Batteries, Faculty of Chemistry, Northeast Normal University , Changchun, Jilin 130024, P. R. China.
School of Materials Science and Engineering, Nanyang Technological University , 50 Nanyang Avenue, Singapore 639798, Singapore.
ACS Appl Mater Interfaces. 2018 Jan 31;10(4):3581-3589. doi: 10.1021/acsami.7b16580. Epub 2018 Jan 18.
A novel core-shell FeO@FeS composed of FeO core and FeS shell with the morphology of regular octahedra has been prepared via a facile and scalable strategy via employing commercial FeO as the precursor. When used as anode material for sodium-ion batteries (SIBs), the prepared FeO@FeS combines the merits of FeS and FeO with high Na-storage capacity and superior cycling stability, respectively. The optimized FeO@FeS electrode shows ultralong cycle life and outstanding rate capability. For instance, it remains a capacity retention of 90.8% with a reversible capacity of 169 mAh g after 750 cycles at 0.2 A g and 151 mAh g at a high current density of 2 A g, which is about 7.5 times in comparison to the Na-storage capacity of commercial FeO. More importantly, the prepared FeO@FeS also exhibits excellent full-cell performance. The assembled FeO@FeS//NaV(PO)OF sodium-ion full battery gives a reversible capacity of 157 mAh g after 50 cycles at 0.5 A g with a capacity retention of 92.3% and the Coulombic efficiency of around 100%, demonstrating its applicability for sodium-ion full batteries as a promising anode. Furthermore, it is also disclosed that such superior electrochemical properties can be attributed to the pseudocapacitive behavior of FeS shell as demonstrated by the kinetics studies as well as the core-shell structure. In view of the large-scale availability of commercial precursor and ease of preparation, this study provide a scalable strategy to develop advanced anode materials for SIBs.
一种新颖的核壳结构 FeO@FeS 由具有八面体形态的 FeO 核和 FeS 壳组成，通过采用商业 FeO 作为前体制备了一种简便且可扩展的策略。当用作钠离子电池（SIBs）的阳极材料时，所制备的 FeO@FeS 结合了 FeS 和 FeO 的优点，分别具有高的储钠容量和优异的循环稳定性。优化的 FeO@FeS 电极表现出超长的循环寿命和出色的倍率性能。例如，在 0.2 A g 的电流密度下经过 750 次循环后，其容量保持率为 90.8%，可逆容量为 169 mAh g，在 2 A g 的高电流密度下，其可逆容量为 151 mAh g，与商业 FeO 的储钠容量相比提高了约 7.5 倍。更重要的是，所制备的 FeO@FeS 还表现出优异的全电池性能。组装的 FeO@FeS//NaV(PO)OF 钠离子全电池在 0.5 A g 的电流密度下经过 50 次循环后，可逆容量为 157 mAh g，容量保持率为 92.3%，库仑效率约为 100%，表明其作为一种有前途的阳极适用于钠离子全电池。此外，还揭示了这种优越的电化学性能可归因于 FeS 壳的赝电容行为，这通过动力学研究以及核壳结构得到了证实。鉴于商业前体制备的大规模可用性和易于制备性，本研究提供了一种可扩展的策略来开发用于 SIBs 的先进阳极材料。
