Chu Xianyu, Meng Fanling, Deng Ting, Lu Yue, Bondarchuk Oleksandr, Sui Manling, Feng Ming, Li Haibo, Zhang Wei
Key Laboratory of Mobile Materials MOE, and School of Materials Science & Engineering, and Electron Microscopy Center, and International Center of Future Science, Jilin University, Changchun 130012, China.
Nanoscale. 2020 Mar 7;12(9):5669-5677. doi: 10.1039/c9nr10473a. Epub 2020 Feb 26.
Engineering multicomponent electroactive materials is an effective strategy to improve electrochemical performance by adjusting the atomic and electronic structure. In this work, we directly synthesize oriented bimetallic CoNi-MOF nanosheets on CFP (carbon fiber paper). The CoNi-MOF/CFP shows high specific capacitance, outstanding rate capability and long-term cycling stability compared to a monometallic Ni-MOF or Co-MOF. By adjusting the Co/Ni molar ratio, CoNi23/CFP (Co : Ni = 2 : 3) displays the highest specific capacitance (2033 F g at 1 A g). The introduction of Co into the Ni-MOF matrix shortens Co/Ni-centered bond distances, resulting in improved bond strength, facilitating the charge transfer and increasing the electrical conductivity of the CoNi-MOF, which were proved by X-ray absorption fine structure (XAFS) spectroscopy, high angle annular dark field (HAADF) imaging, and electrochemical impedance spectroscopy (EIS). Our study demonstrates the origin of performance improvements and, therefore, may provide a feasible scheme to unlock high-performance MOF electrode materials.
设计多组分电活性材料是通过调整原子和电子结构来提高电化学性能的有效策略。在这项工作中，我们直接在CFP（碳纤维纸）上合成了取向双金属CoNi-MOF纳米片。与单金属Ni-MOF或Co-MOF相比，CoNi-MOF/CFP表现出高比电容、出色的倍率性能和长期循环稳定性。通过调整Co/Ni摩尔比，CoNi23/CFP（Co : Ni = 2 : 3）表现出最高的比电容（在1 A g下为2033 F g）。将Co引入Ni-MOF基体中缩短了以Co/Ni为中心的键距，导致键强度提高，促进了电荷转移并增加了CoNi-MOF的电导率，这通过X射线吸收精细结构（XAFS）光谱、高角度环形暗场（HAADF）成像和电化学阻抗谱（EIS）得到了证实。我们的研究揭示了性能提升的根源，因此可能为开发高性能MOF电极材料提供一个可行的方案。
