Structure and capacitive properties of gallic acid functionalized Ni/Co-DABD MOF@NH2-MXene electrode

Gallic acid (GA) chelates with exposed metal active sites of Ni/Co-DABD MOF, effectively protecting metal ions and elevating MOF coordination stability. • The GA-modified Ni/Co-DABD MOF@NH₂-MXene composite electrode delivers a high specific capacitance of 2044 F g -1 at 1 A g -1 with superior rate capability and cycling durability. • GA modification strengthens the interfacial synergy between MOF and NH₂-MXene, significantly boosting charge transfer efficiency and structural stability of the composite. The limited active sites and poor electrochemical structural stability of metal-organic frameworks (MOF) severely limit their application in electrochemical energy storage. In this study, we used the acid properties of gallic acid (GA) as an etching agent to etch MOF surface active sites. Subsequently, the protonated GA is further chelated with the exposed metal active site, which can effectively protect the metal ions. At the same time, GA provides a large number of phenolic hydroxyl groups, which greatly improves the coordination stability of MOF. A new MOF@MXene composite electrode material was obtained by solvothermal synthesis of GA-modified MOF and aminated MXene. The electrochemical test results show that the new MOF@MXene composite electrode material synthesized by this scheme has high specific capacitance and high rate stability. The functional modification of MOF by GA greatly improves the synergistic binding performance between MOF and MXene, and thus significantly improves the electrochemical stability of composite electrode materials. The mechanism of the electrochemical reaction was investigated by in-situ X-ray diffraction and theoretical calculation. In this paper, the functional mechanism of polyphenols on MOF is described, which provides a new idea for the electrochemical application of MOF. The GA-modified Ni/Co-DABD MOF@NH₂-MXene composite electrode delivers a high specific capacitance of 2044 F g -1 at 1 A g -1 with superior rate capability and cycling durability. Download: Download high-res image (296KB) Download: Download full-size image