Pyridine-Functionalized Naphthalene Diimide-Based Cross-Linked Polymer for Efficient Supercapacitor Applications
Madan R. Biradar, Chepuri R.K. Rao, Sidhanath V. Bhosale, Sheshanath V. Bhosale
Abstract
In the electrochemical energy storage system, redox-active organic polymers have great attraction due to their eco-friendly, easily available raw materials, variation of design architecture with tailoring their molecular structure, and excellent redox-active functional groups. In this paper, we designed a novel pyridine-functionalized naphthalene diimide cross-linked polymer as an electrode material. The synthesized naphthalene diimide appended the pyridine cross-linked polymer with three-dimensional network structures, showing an outstanding electrochemical performance in SC applications. The monomer NDI-PY-AC is synthesized by using 1,4,5,8-naphthalenetetracarboxylic dianhydride (NDA) and PY-AC by a simple imidization–condensation reaction. Furthermore, the PNDI-PY-AC polymer was synthesized via radical polymerization using AIBN as an initiator. The cross-linked PNDI-PY-AC polymer was confirmed using solid-state 13 C NMR and Fourier transform infrared (FT-IR) spectroscopic techniques. The PNDI-PY-AC polymer morphology of the material was examined by field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) images. The specific surface area and porosity of the polymer were confirmed by the Brunauer–Emmett–Teller (BET) method. The cross-linked-type morphology of the polymer resolved the solubility issue of the electrode material in the electrolyte. The practical applicability of PNDI-PY-AC is evaluated using symmetric two-electrode Swagelok cell assembly. The PNDI-PY-AC/GF electrode acts as a cathode and anode in the solid-state synchronous condenser (SSC) device, which shows a specific capacitance ( C sp ) of 202.85 F g –1 at 0.5 A g –1 current density. The SSC device shows a high energy density of 49.69 Wh kg –1 with a power density of 1259.99 W kg –1 at a discharge current density of 0.5 A g –1 . We observed that the PNDI-PY-AC/GF electrode exhibited an original capacitance retention of 92.86% after 5000 GCD cycles at 2 A g –1 current density.