Exploring the feasibility of a two-dimensional layered cobalt-based coordination polymer for supercapacitor applications: effect of electrolytic cations

Abstract

Coordination polymers have attracted much interest in energy-related applications due to their adaptable structures and unique photophysical and chemical properties. In this study, a coordination polymer, Co-CP, was synthesized using a mixed ligand strategy via a slow diffusion technique. Single-crystal X-ray diffraction studies confirmed the characteristic two-dimensional structure of Co-CP, and plate-like morphology was authenticated through SEM images. Co-CP facilitates ion transport and efficient charge transfer processes, making it an ideal active material for supercapacitor applications. The results from the electrochemical studies demonstrate excellent supercapacitor properties for Co-CP, exhibiting a specific capacitance of 1092 F g⁻¹ at 1.5 A g⁻¹ in 7 M NaOH. Furthermore, the kinetic effect of the electrolyte cation was also investigated in a two-electrode asymmetric supercapacitor (ASC) system by preparing three different gels (NaOH-PVA, KOH-PVA, and LiOH-PVA). Similar trends were observed for the ASC device, with the highest energy density of 17 W h Kg⁻¹ at a power density of 1200 W Kg⁻¹ in NaOH-PVA gel. Overall, the results suggest that Co-CP is a promising active material for supercapacitor applications, and the choice of electrolyte cation has a remarkable impact on the electrochemical performance of the device. This study provides valuable insights for the development and optimization of high-performance supercapacitors based on coordination polymers.