ABSTRACT
Chalcogenides, a promising class of electrode materials, attracted massive popularity owing to their exciting features of high conductive nature, high capacity, rich redox activities, and structural functionalities, making them the first choice for the electrochemical energy domain. This paper reported a new NiSe2-CuSe nanocomposite prepared via a wet-chemical synthesis followed by a low-cost and simple hydrothermal reaction. The physical characterization showed cubes and nanoparticles type morphological features of NiSe2 and CuSe products, while their composite reveals a combined morphological characteristic. The electrochemical properties were tested in an aqueous solution, demonstrating that the NiSe2-CuSe nanocomposite exhibits a high capacity of 376 C g-1, low resistance, good reversibility and rate capability in a three-electrode mode than bulk counterparts. For practical aspects, a battery-hybrid supercapacitor (BHSC) is developed with NiSe2-CuSe nanocomposite, and activated carbon (AC) serves as cathode and anode in two-cell mode operation. The built NiSe2-CuSe||AC/KOH BHSC expanded the voltage to 1.8 V and delivered the highest capacitance of 148 F g-1 and 55 F g-1 from 1 to 10 A g-1, suppressing most of the previously existing literature reports. Also, our built NiSe2-CuSe||AC/KOH BHSC displayed a high-power delivery of 8928 W kg-1 at a maximum energy density of 66.6 W h kg-1 and retained 91.7% capacitance after a long way of 10,000 cycles. These outstanding results demonstrate that metal selenides can be effectively utilized as alternative electrodes with high energy, rate performance, and long-term durability for advanced energy conversion and storage devices.
Subject(s)
Charcoal , Electric Power Supplies , Electric Capacitance , Electric Conductivity , ElectrodesABSTRACT
This study portrays a facile wet-chemical synthesis of FeSe2/TiO2 nanocomposites for the first time for advanced asymmetric supercapacitor (SC) energy storage applications. Two different composites were prepared with varying ratios of TiO2 (90 and 60%, symbolized as KT-1 and KT-2) and their electrochemical properties were investigated to obtain an optimized performance. The electrochemical properties showed excellent energy storage performance owing to faradaic redox reactions from Fe2+/Fe3+ while TiO2 due to Ti3+/Ti4+ with high reversibility. Three-electrode designs in aqueous solutions showed a superlative capacitive performance, with KT-2 performing better (high capacitance and fastest charge kinetics). The superior capacitive performance drew our attention to further employing the KT-2 as a positive electrode to fabricate an asymmetric faradaic SC (KT-2//AC), exceeding exceptional energy storage performance after applying a wider voltage of 2.3 V in an aqueous solution. The constructed KT-2/AC faradaic SCs significantly improved electrochemical parameters such as capacitance of 95 F g-1, specific energy (69.79 Wh kg-1), and specific power delivery of 11529 W kg-1. Additionally, extremely outstanding durability was maintained after long-term cycling and rate performance. These fascinating findings manifest the promising feature of iron-based selenide nanocomposites, which can be effective electrode materials for next-generation high-performance SCs.
ABSTRACT
Hierarchical nanostructures with appropriate morphology and surface functionalities are highly desired to achieve an optimized electrochemical property for active electrode materials. This work renders the facile hydrothermal synthesis of CdO, SnO2, and CdO-SnO2 nanocomposite, and their capacitive performance was tested. The formation of the pure samples and their composite was committed by low-temperature Raman spectroscopy and x-ray diffraction studies which revealed the tetragonal and cubic structures of CdO and SnO2 powder samples with good crystallinity and purity. The morphological postmortem reveals the formation of nanoparticles morphology of CdO with a highly smooth surface appearance. Besides, the SnO2 illustrates the morphology of the micro flowers composed of ultrathin nanosheets. More specifically, the electrochemical properties indicate the pseudocapacitive charge storage mechanism based on cyclic voltammetry and chronopotentiometry analysis. The CdO-SnO2 composite electrode displayed a higher capacitance due to additional pores/space offered for active sites and continuously allowed electrolyte ions to interact with the inner/outer surface of the electrode. These exciting findings led us to design and fabricate battery hybrid supercapacitors (BHSC) from CdO-SnO2, and activated carbon (AC), referred to as CdO-SnO2//AC BHSC, attains a high power delivery (5717 W/kg), and a maximum energy density of 42 Wh/kg at low discharge rate. Noteworthy, a stable cycling performance was obtained with only 91.3% retention after 8000 cycling at a large discharge current of 10 A/g, denoting the magnificent durability of the active electrode material.
