Realizing higher-performance supercapacitor using three-dimensional cadmium-based coordination polymer

Abstract

In order to enhance energy density of supercapacitors, it is a route to develop new high-performance electrode materials. Coordination polymers (CPs) as the electrode materials of supercapacitors have received considerable attention, due to them owning redox active centers (metal ions/organic ligands) and the porosity, but developing high-performance and low-cost CP-based electrode materials remains a challenging task. Herein, a novel three-dimensional (3D) cadmium-based CP [Cd(BGPD)(H2O)2] (Cd−CP; BGPD = N,N′-bis(glycinyl)pyromellitic diimide) with low-cost has been synthesized by a facile method. When served as an electrode material of supercapacitors, in a three-electrode system, the specific capacitance of Cd−CP is up to 1339 F g−1 under 1 A g−1 (equivalent to a specific capacity of 167 mAh g−1). Notably, an asymmetrical supercapacitor, Cd−CP//rGO, as a two-electrode system constructed by the rGO electrode and the Cd−CP electrode, exhibits a superior energy density of 13.3 Wh kg−1 at 0.80 kW kg−1, and a general cycle capability with the capacitance retention of 61.3 % after 4000 cycles. Our work provides a new route for searching higher-performance electrode materials with low-cost and demonstrates the application potential of Cd−based CPs as the electrode materials of supercapacitors.