Redox active multi-layered Zn-pPDA MOFs as high-performance supercapacitor electrode material

Metal-organic frameworks (MOFs), which combine organic and inorganic components, are promising materials for energy storage. The conjugated structure of MOFs offers excellent electrical conductivity and charge storage performance. In this study, we introduce Zn-p-phenylenediamine (Zn-pPDA) MOFs for a first time in energy storage devices, and we also use a green and facile synthesis method for the preparation of the materials. Multi-layered Zn-pPDA MOF nanostructures with a thickness of 1-5 mu m and a width of similar to 20 nm are synthesised using liquid-liquid interfacial reactions. Their MOF complexes are used to fabricate positive electrodes for supercapacitors. The MOF supercapacitors exhibit high energy and power densities of approximately 62.8 Wh/kg and 4500 W/kg, respectively. Additionally, excellent cyclability with similar to 96% capacitive retention after 2000 cycles is obtained. We show that the synthesis method can open a new pathway for formulating pPDA-ligand-based MOFs, and that the Zn-pPDA MOF is a highly promising material for future energy storage devices. (C) 2018 Elsevier Ltd. All rights reserved.