Self‐Supporting CuCo 2 S 4 Microspheres for High‐Performance Flexible Asymmetric Solid‐State Supercapacitors

Quaternary Cu2FeSnS4/PVP/rGO Composite for Supercapacitor Applications

Electrochemical energy storage is a current research area to address energy challenges of the modern world. The Cu2FeSnS4/PVP/rGO-decorated nanocomposite using PVP as the surface ligand was explored in a simple one-step solvothermal route, for studying their electrochemical behavior by designing asymmetric hybrid supercapacitor devices. The full cell three-electrode arrangements delivered 748 C/g (62.36 mA h/g) at 5 mV/s employing CV and 328 F/g (45.55 mA h/g) at 0.5 A/g employing GCD for the Cu2FeSnS4/PVP/rGO electrode. The half-cell two-electrode device can endow with 73 W h/kg and 749 W/kg at 1 A/g energy and power density. Furthermore, two Cu2FeSnS4/PVP/rGO//AC asymmetric devices connected in series for illuminating a commercial red LED more than 1 min were explored. This work focuses the potential use of transition-metal chalcogenide composite and introduces a new material for designing high-performance supercapacitor applications.

A facile synthesis of a NiMoO4@metal-coated graphene-ink nanosheet structure towards the high energy density of a battery type-hybrid supercapacitor

Recently, reagent-based electrode materials (urea, ammonium fluoride, hexamethylenetetramine, l-cysteine, acetic acid, and triethylamine) have received great attention in numerous applications (e.g., solar cells, fuels cells, and battery-type hybrid supercapacitors (BHSCs)). Herein, we designed a wrinkle-type nanosheet structure with a mixture of NiMoO4 using triethylamine via a hydrothermal synthesis. The dual metal ions of Ni2+/Ni3+ and Mo2+/Mo3+ can significantly boost the energy storage performance by the support of triethylamine. NiMoO4 was deposited onto a nickel foam substrate without any binders, and the electrode exhibited a high specific capacitance/capacity of 415.66 F g-1 (249.4 mA h g-1) at 8 mA cm-2 with a good long-term cycling performance over 5000 cycles. Moreover, we assembled flexible HSCs (NiMoO4@MCG-ink) as the core, and the outer material delivered a high specific energy of 40.14 W h kg-1 at 1066.39 W kg-1. The HSC device demonstrated excellent long-term durability with a capacity retention of 99%, and various bending conditions were also tested for flexibility of the device after 5000 cycles. Furthermore, a series of two HSC devices were efficient to light up red and green light-emitting diodes (LEDs) for about 60 minutes, indicating its potential applications in energy storage devices. Hence, our work provides new insights into the preparation of new electrode materials for high energy storage performance of lithium-ion batteries (LIBs) and SCs.

Supercapacitive Performances of Ternary CuCo2S4 Sulfides

Currently, ternary CuCo₂S₄ sulfides are intensively investigated as electrode materials for electrochemical capacitors due to their low cost, high conductivity, and synergistic effect. The research of CuCo₂S₄ materials for energy storage has gradually grown from 2016. The supercapacitive performances of CuCo₂S₄ electrodes for electrochemical capacitors are briefly reviewed in this work. The structure, morphology, and particle size of CuCo₂S₄ are related to the synthesis conditions and electrochemical performances. The thin films of CuCo₂S₄ nanostructures deposited on conductive substrates and their composites both show better properties than single CuCo₂S₄. CuCo₂S₄ and its composites reveal large potential for asymmetric capacitors, delivering high energy densities. However, there is still much new space remaining for future research. The possible development directions, challenges, and opportunities for CuCo₂S₄ materials are also discussed.