Insight into the diversity of dimensionality in silver-based coordination polymers for enhanced supercapacitor performance

Abstract

Novel silver-based coordination polymers, [(2Ag)_0.5·(4,4′-bipy)_0.5·(DNB)]_n and {[Ag(4,4′-bipy)]·(NDC)_0.5·2H₂O}_n (where DNB = 2,4-dinitrobenzoate and NDC = 2,6-naphthalene dicarboxylate), denoted as DNB-CP and NDC-CP, respectively, have been synthesized by a one-pot simple hydrothermal process to be used as high-performance electrode materials for supercapacitor applications. Structural, microstructural, and compositional analyses of the synthesized coordination polymers have been performed using various techniques. The electrochemical behavior of the fabricated coordination polymer-based electrode materials is examined using cyclic voltammetry (CV) and galvanostatic charge/discharge (GCD). The silver-based coordination polymers act as adequate electrode materials, and their supercapacitor performance depends upon the structure dimensionality. The thermal stability of the coordination polymers is affected by the dimensionality, which is confirmed by thermogravimetric analysis (TGA). The coordination polymer DNB-CP forms a 1D polymeric chain, whereas NDC-CP shows combined ionic and coordinate bonding interactions. As the dimensionality increased in the CPs, the rate of ion transport and efficient charge transfer processes increased, resulting in enhanced electrochemical properties. The DNB-CP electrode delivers a good specific capacitance of 971.08 mF cm⁻² at a 10 mV s⁻¹ scan rate after 500 cycles, which is much better than the NDC-CP showing a specific capacitance of 78.81 mF cm⁻² at 50 mV s⁻¹. Furthermore, the electrodes fabricated from DNB-CP can be used in electrochemical energy storage due to their exceptional electrochemical properties.