A new path to high-performance supercapacitors: Utilizing ag-embedded CoFe-phosphate and Ti3C2MXene as hybrid electrodes

This study addresses the issue of poor performance in assembled supercapacitor devices, which is attributed to the slow kinetics and structural instability of positive electrodes and the lower capacitance of carbon-based negative electrodes. To address this challenge, the authors propose a sustainable solution that involves using Ag-embedded CoFe-phosphate (CFPAg) and Ti3C2MXene as positive and negative electrodes, respectively, to create a hybrid supercapacitor (HS) device. The CFPAg electrode, made up of porous nanoflakes decorated with nanospheres of CoFe-phosphate material, is deposited on Ni-foam without the need of a binder, using a simple hydrothermal method. The MXene electrode is chemically synthesized and deposited on Ni-foam as the negative electrode. The results of the electrochemical study show that the CFPAg electrode exhibits a specific capacity of 1021 mF/cm2with 80.5 % cyclic stability over 10,000 cycles, while the MXene electrode shows a specific capacity of 177.6 mF/cm2with a cyclability of 84.7 % over 10,000 cycles. The HS device, fabricated using CFPAg and MXene electrodes, displays an areal capacitance of 79.6 mF/cm2and provides excellent cyclic stability of 96 % over approximately 39,000 cycles. It also exhibits a high energy density of 24.7 μWh/cm2at a power density of 0.75 mW/cm2when measured at 2 mA/cm2applied current density. This work serves as a foundation for developing a range of electrode materials for next-generation energy storage devices, providing a sustainable and effective solution to improve supercapacitor device performance and longevity.