Tuning dimensionality and linkage in metal–organic frameworks for enhanced electrochemical energy storage

Abstract

In this study, we report the synthesis and comparative analysis of two metal–organic frameworks (MOFs) assembled into distinct dimensional architectures: a three-dimensional pillared-layered structure (3D-PL-MOF) and a two-dimensional layered structure (2D-L-MOF). Dimensional control was achieved by tuning the reaction conditions, resulting in frameworks with remarkable metal ion and ligand connectivities. 3D-PL-MOF exhibited a robust pillared-layered framework, whereas 2D-L-MOF displayed a planar layered arrangement. Both the MOFs were extensively characterized using advanced techniques to investigate the structural features, morphology, and thermal stability. Electrochemical characterization measurements were performed to elucidate the role of dimensionality in the charge storage mechanism. The results show that 3D-PL-MOF exhibits significantly higher specific capacitance compared to 2D-L-MOF, with a specific capacitance of 355 F g⁻¹ at 1 A g⁻¹, and excellent cyclic stability (92.85% after 10 000 GCD cycles). Furthermore, when assembled into an asymmetric supercapacitor device, it achieves an energy density of 31.63 W h kg⁻¹ and a power density of 749.87 W kg⁻¹. These findings underscore the pivotal role of structural dimensionality in governing the physicochemical and electrochemical performance of MOFs, and offer valuable insights for designing advanced materials for energy storage applications.