We present here the preparation of a novel chemically immobilized mixed-metal ion-containing triazine thiolate (C ₃ N ₃ S ₃ ) polymer electrocatalyst (M–TCA) on a copper (Cu) surface.

Ethanol–water etched Prussian blue analog nanocages decorated with molybdenum disulfide nanoflowers exhibit remarkable electrocatalytic activity toward the OER. The catalyst delivers an excellent OER activity with an overpotential of only 260 mV to obtain a current density of 10 mA cm⁻².

Supercapacitors (SCs) coupled with redox materials have been extensively investigated to maximize the energy density of SCs. Common metal–organic frameworks explicitly used for this purpose are Prussian blue analogs (PBAs). However, their low conductivity and number of external electroactive sites hinder their capacitance and reaction rate. Our work focuses on a material-level optimization strategy, including morphology modification and superstructure fabrication of PBA. We report the synthesis of Co–Co@Ni–Fe trimetallic core–shell PBA nanocubes containing an Fe^II/III redox couple in the Ni–Fe PBA shell over the conductive Co–Co PBA core. This complex underwent a reversible redox reaction and was further encapsulated in a polypyrrole (PPy) network as a redox additive to prepare a novel polymer-encapsulated double-PBA nanocube composite (Co–Co@Ni–Fe PBA–PPy). The composite exhibited a faradaic non-capacitive diffusion-dominated charge storage ability. It yielded an improved specific capacity of 318.1 C g⁻¹ at 1 A g⁻¹ with a capacity retention of 90% over 2000 cycles @15 A g⁻¹. Furthermore, an asymmetric supercapacitor based on Co–Co@Ni–Fe PBA–PPy and activated carbon electrodes delivered a maximum energy density of 20 W h kg⁻¹ at a power density of 808.9 W kg⁻¹ within a 1.6 V voltage window. The electrochemical analysis demonstrated a considerable improvement in the charge-storage performance due to an increase in electron transfer, electrolyte diffusion, and electroactive area via strong electronic coupling between the Co–Co@Ni–Fe core–shell PBA and the PPy. Furthermore, this work helps to differentiate the composite's current contributions from the PBA and PPy. The detailed electrochemical characterization steps of these methods concerning redox additives integrated into conducting polymers are provided in this work.

Supercapacitors are prospective energy storage devices for electronic devices due to their high power density, rapid charging and discharging, and extended cycle life. Materials with limited conductivity could have low charge-transfer ions, low rate capability, and low cycle stability, resulting in poor electrochemical performance. Enhancement of the device’s functionality can be achieved by controlling and designing the electrode materials. Graphene oxide (GO) has emerged as a promising material for the fabrication of supercapacitor devices on account of its remarkable physiochemical characteristics. The mechanical strength, surface area, and conductivity of GO are all quite excellent. These characteristics make it a promising material for use as electrodes, as they allow for the rapid storage and release of charges. To enhance the overall electrochemical performance, including conductivity, specific capacitance (C_s), cyclic stability, and capacitance retention, researchers concentrated their efforts on composite materials containing GO. Therefore, this review discusses the structural, morphological, and surface area characteristics of GO in composites with metal oxides, metal sulfides, metal chalcogenides, layered double hydroxides, metal–organic frameworks, and MXene for supercapacitor application. Furthermore, the organic and bacterial functionalization of GO is discussed. The electrochemical properties of GO and its composite structures are discussed according to the performance of three- and two-electrode systems. Finally, this review compares the performance of several composite types of GO to identify which is ideal. The development of these composite devices holds potential for use in energy storage applications. Because GO-modified materials embrace both electric double-layer capacitive and pseudocapacitive mechanisms, they often perform better than pristine by offering increased surface area, conductivity, and high rate capability. Additionally, the density functional theory (DFT) of GO-based electrode materials with geometrical structures and their characteristics for supercapacitors are addressed.