The rise of 2D conductive metal-organic framework: Cu3(HHTP)2 d- π MOF for integrated battery-supercapacitor hybrids

Two-dimensional (2D) conductive metal-organic frameworks (c-MOFs) being a family of porous materials have emerged as novel electrode materials for energy storage devices. The inherent unique properties of 2D c-MOFs, such as large surface area, high porosity, improved electrical conductivity, and fast ion transport, make them ideal candidates for electrochemical hybrid battery-supercapacitor applications. However, the exploration of 2D c-MOFs for hybrid energy storage devices with admirable conductive and electrochemical properties has rarely been investigated. Herein, 2D conductive copper-based MOF [Cu3(HHTP)2] (HHTP = 2,3,6,7,10,11-hexahydroxytriphenylene) was synthesized for hybrid battery-supercapacitor application. The conductive 2D layered framework exhibited low resistance, quick diffusion, and electron transfer. The Cu3(HHTP)2 has shown the maximum capacity of 135 C g−1 along with 32 W h kg−1 and 2100 W kg−1 of energy and power density, respectively. The corresponding hybrid device exhibits long cyclic stability (99% after 1000 GCD cycles) and columbic efficiency (94%) at a current density of 4 A g−1. In addition, Dunn's model was fitted to determine capacitive/diffusive contributions and the regression parameters (k1 and k2). This work provides a new direction for utilizing the 2D c-MOFs for hybrid battery-supercapacitor energy storage devices.