Electrochemical investigation of copper 1D conductive polymer for hybrid supercapacitor applications

The rising demand for advanced energy storage devices having superior energy and power density has propelled the development of hybrid supercapacitors by integrating capacitive and battery-grade materials in a single device. This drives expedition is ongoing research for the development of advanced materials. In this regard, metal-organic frameworks (MOF) comprising metal nodes and organic ligands containing nitrogen atom evolved as leading candidates for their customized and extraordinary features. Here, we have synthesized copper-based 1D conductive MOF from 2,6-pyridinedicarboxylic acid (PDA) and structurally characterized by using single- crystal X-ray diffraction, FT-IR, TGA and elemental analyzer techniques. PDA ligands are connected by copper ions with 1D pi-d conjugated layers. The presence of oxygen and nitrogen heteroatoms in PDA promotes high surface area, porosity as well as facilitates more electrolyte-ions interclation to active sites, resulting in increased redox potential and charge storage responsible for enhanced conductivity and stable framework. Detailed electrochemical performance was investigated through a three-electrode assembly using CV, GCD, and EIS techniques. Analysis of the material exhibited characteristics of advanced battery-grade material. Based on its inherent electrochemical features, it was practically validated by integrating Cu-PDA-MOF (battery-grade) as positive electrode and activated carbon (capacitive-grade) as negative electrode in two-electrode set up. The hybrid device possessed extraordinary electrochemical features with specific capacity of 160.59C/g, energy density of 31.23 Wh/kg, and power density of 1400 W/kg. Remarkably, the hybrid device showed 99.8 % cyclic stability even after 5000 GCD cycles. These advanced electrochemical features underscore Cu-PDA-MOF as a highly attractive material for futuristic energy storage devices.