In Situ Growth of Ni-MOF Nanorods Array on Ti3C2Tx Nanosheets for Supercapacitive Electrodes

For the energy supply of smart and portable equipment, high performance supercapacitor electrode materials are drawing more and more concerns. Conductive Ni-MOF is a class of materials with higher conductivity compared with traditional MOFs, but it continues to lack stability. Specifically, MXene (Ti3C2Tx) has been employed as an electrochemical substrate for its high mechanical stability and abundant active sites, which can be combined with MOFs to improve its electrochemical performance. In this paper, a novel Ni-MOF nanorods array/Ti3C2Tx nanocomposite was prepared via a facile hydrothermal reaction, which makes good use of the advantages of conductive Ni-MOF and high strength Ti3C2Tx. The high density forest-like Ni-MOF array in situ grown on the surface of Ti3C2Tx can provide abundant active electrochemical sites and construct a pathway for effective ion transport. The formation of a "Ti-O center dot center dot center dot Ni" bond accomplished during an in situ growth reaction endows the strong interfacial interaction between Ni-MOF and Ti3C2Tx. As a result, the Ni-MOF/Ti3C2Tx nanocomposite can achieve a high specific capacitance of 497.6 F center dot g(-1) at 0.5 A center dot g(-1) and remain over 66% of the initial capacitance when the current density increases five times. In addition, the influence of the Ti3C2Tx concentration and reaction time on the morphology and performance of the resultant products were also investigated, leading to a good understanding of the formation process of the nanocomposite and the electrochemical mechanism for a supercapacitive reaction.