Excellent lithium storage performance of Ni-MOFs/GO composite as anode in lithium ion battery†

Abstract

Metal–organic frameworks (MOFs) have been perceived as promising electrode materials in lithium ion batteries (LIBs) due to their tunable three-dimensional porous frameworks and large surface areas. However, the coordinate bonds between metallic ions and organic ligands in MOFs are easily broken during the redox process, resulting in structural breakage and poor electrochemical performance. In this study, graphene oxide (GO) has been applied as a matrix to anchor Ni²⁺ through carboxyl groups, thereby forming Ni-MOFs in situ on the surface and effectively enhancing the structural stability of Ni-MOFs. When used as an anode in an LIB, Ni-MOFs/GO can present a specific capacity of 740.8 mA h g⁻¹ at 50 mA g⁻¹ with almost no capacity degradation after 100 cycles. This performance can be attributed to the large d–π electron conjugation, which not only contributes to rapid electron transfer but also benefits the delocalization of charge. Additionally, the GO matrix can effectively prevent the agglomeration of Ni-MOF particles, which also aids the structural stabilization of Ni-MOFs in the charge/discharge process, thus enhancing the electrochemical performance of Ni-MOFs/GO.