Sun Jie, Yu Xianbo, Zhao Shihang, Chen Hongmei, Tao Kai, Han Lei
State Key Laboratory Base of Novel Functional Materials and Preparation Science, School of Materials Science and Chemical Engineering, Ningbo University, Ningbo, Zhejiang 315211, China.
Inorg Chem. 2020 Aug 17;59(16):11385-11395. doi: 10.1021/acs.inorgchem.0c01157. Epub 2020 Jul 31.
The composition-tuned, structure-modified, and morphology-controlled nanoscale metal-organic frameworks (MOFs) are quite important to improve the electrochemical performances for supercapacitors. In this work, a solvent-controlled method to prepare amino-functionalized bimetal MOFs with various morphologies is proposed. Three different morphologies of NiCo-MOFs, such as nanospheres, nanosheet-assembled hollow spheres (NSHSs), and rhombus sheets, have been successfully synthesized by using different solvents. The as-prepared three nanoscale NiCo-MOFs are comparatively characterized and are endowed a possible mechanism on nucleation and crystal growth controlling morphology. When used as electrode materials for supercapacitors, all NiCo-MOFs have excellent electrochemical properties. Specifically, the NiCo-MOF NSHS owns the best specific capacitance, which can achieve 1126.7 F g at the current density of 0.5 A g and maintain 93% of its original capacitance at the current density of 10 A g after 3000 charge-discharge cycles. Moreover, an asymmetric supercapacitor device (NiCo-MOF NSHS//AC) assembled with NiCo-MOF NSHS as the positive electrode and activated carbon (AC) as the negative electrode achieves an energy density of 20.94 Wh kg at a power density of 750.84 W kg. This work is facile and highly reproducible and can be extended to prepare other nano-MOFs in energy storage and conversion fields. In addition, it opens up an effective approach to synthesizing amino-functionalized MOFs by a solvent-controlled method without any other changes in the experimental conditions.
组成可调、结构改性和形态可控的纳米级金属有机框架（MOF）对于提高超级电容器的电化学性能非常重要。在这项工作中，提出了一种溶剂控制法来制备具有各种形态的氨基功能化双金属MOF。通过使用不同的溶剂，成功合成了三种不同形态的NiCo-MOF，如纳米球、纳米片组装空心球（NSHS）和菱形片。对所制备的三种纳米级NiCo-MOF进行了比较表征，并赋予了一种关于成核和晶体生长控制形态的可能机制。当用作超级电容器的电极材料时，所有NiCo-MOF都具有优异的电化学性能。具体而言，NiCo-MOF NSHS具有最佳的比电容，在电流密度为0.5 A g时可达到1126.7 F g，在3000次充放电循环后，在电流密度为10 A g时仍保持其原始电容的93%。此外，以NiCo-MOF NSHS为正极、活性炭（AC）为负极组装的不对称超级电容器器件（NiCo-MOF NSHS//AC）在功率密度为750.84 W kg时实现了20.94 Wh kg的能量密度。这项工作简便且具有高度可重复性，可扩展到储能和转换领域中制备其他纳米MOF。此外，它开辟了一种通过溶剂控制法合成氨基功能化MOF的有效途径，而无需在实验条件上进行任何其他改变。
