Fabrication of an MOF-derived heteroatom-doped Co/CoO/carbon hybrid with superior sodium storage performance for sodium-ion batteries
Fabrication of an MOF-derived heteroatom-doped Co/CoO/carbon hybrid with superior sodium storage performance for sodium-ion batteries
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DOI：
10.1039/c7ta03939e
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发表时间：
2017-08-07
影响因子：
11.9
通讯作者：
Yamauchi, Yusuke
中科院分区：
文献类型：
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作者：
Kaneti, Yusuf Valentino;Zhang, Jun;Yamauchi, Yusuke
金属有机骨架(MOF)由于其组成、结构和孔径的高度可控性，作为制备多孔杂化材料的先驱体受到了极大的关注。然而，目前MOF衍生材料作为钠离子电池负极材料的研究还很少。在本工作中，我们报道了以双金属Ni-Co-ZIF为起始前驱体，制备了掺镍的Co/CoO/N掺杂碳(NC)杂化材料。Ni掺杂的Co/CoO/NC杂化材料具有高度的微孔结构，比表面积高达552m(2)g(-1)。作为钠离子电池负极材料，掺杂镍的Co/CoO/NC杂化材料既具有良好的倍率性能，在500 mA g(-1)的大电流密度下放电容量高达218 mA h g(-1)，又具有良好的循环稳定性，500 mA g(-1)循环100次后仍能保持218.7 mA h g(-1)的高容量，容量保持率为87.5%。Ni掺杂Co/CoO/NC杂化材料优异的电化学性能可以归因于多种因素的协同作用，包括：(I)碳基质的存在，它在碱化/脱盐过程中提供防止聚集和粉化的保护；(Ii)高度微孔的性质，以及少数介孔的存在，有助于更好地插入/去插入Na+离子；(Iii)Ni掺杂，通过部分取代将缺陷位引入CoO的原子结构中，从而提高CoO(CoO)组分的导电性，从而提高整个杂化材料的导电性；以及(Iv)N掺杂，通过创建缺陷位，促进钠离子(Na+)在碳层中更快的迁移速度，从而改善杂化材料中碳骨架的导电性。
Metal-organic frameworks (MOFs) have gained significant attention as precursors for the fabrication of porous hybrid materials due to their highly controllable composition, structure and pore size. However, at present, MOF-derived materials have rarely been investigated as anode materials for sodium-ion batteries. In this work, we report the fabrication of a Ni-doped Co/CoO/N-doped carbon (NC) hybrid using bimetallic Ni-Co-ZIF as the starting precursor. The resulting Ni-doped Co/CoO/NC hybrid is highly microporous with a high specific surface area of 552 m(2) g(-1). When employed as an anode material for sodium-ion batteries, the Ni-doped Co/CoO/NC hybrid exhibited both good rate performance with a high discharge capacity of 218 mA h g(-1) at a high current density of 500 mA g(-1) and good cycling stability, as a high discharge capacity of 218.7 mA h g(-1) can be retained after 100 cycles at 500 mA g(-1), corresponding to a high capacity retention of 87.5%. The excellent electrochemical performance of the Ni-doped Co/CoO/NC hybrid for SIBs may be attributed to the synergistic effects of various factors, including: (i) the presence of a carbon matrix which provides protection against aggregation and pulverization during sodiation/desodiation; (ii) the highly microporous nature along with the presence of a few mesopores which facilitates better insertion/de-insertion of Na+ ions; (iii) the Ni-doping which introduces defect sites into the atomic structure of CoO via partial substitution, thus enhancing the conductivity of the cobalt oxide (CoO) component and hence, the overall hybrid material, and (iv) the N-doping which promotes a faster migration speed of sodium ions (Na+) across the carbon layer by creating defect sites, thereby improving the conductivity of the carbon frameworks in the hybrid material.