In-situ growth of flower-like CuS microsphere on carbonized cotton for high-performance flexible supercapacitor

Application of Copper-Sulfur Compound Electrode Materials in Supercapacitors

Supercapacitors (SCs) are a novel type of energy storage device that exhibit features such as a short charging time, a long service life, excellent temperature characteristics, energy saving, and environmental protection. The capacitance of SCs depends on the electrode materials. Currently, carbon-based materials, transition metal oxides/hydroxides, and conductive polymers are widely used as electrode materials. However, the low specific capacitance of carbon-based materials, high cost of transition metal oxides/hydroxides, and poor cycling performance of conductive polymers as electrodes limit their applications. Copper-sulfur compounds used as electrode materials exhibit excellent electrical conductivity, a wide voltage range, high specific capacitance, diverse structures, and abundant copper reserves, and have been widely studied in catalysis, sensors, supercapacitors, solar cells, and other fields. This review summarizes the application of copper-sulfur compounds in SCs, details the research directions and development strategies of copper-sulfur compounds in SCs, and analyses and summarizes the research hotspots and outlook, so as to provide a reference and guidance for the use of copper-sulfur compounds.

Electrochemical Performance of Corn Waste Derived Carbon Electrodes Based on the Intrinsic Biomass Properties

The exploration of cost-effective and sustainable biomass-derived carbon materials as electrodes for energy conversion and storage has gained extensive attention in recent research studies. However, the selection of the biomass and the electrochemical performance regulation of the derived biochar, as well as their interrelationship still remain challenging for practical application. Herein, corn wastes with high carbon content (>40%), corn cob and corn silk, were selected as precursors for the preparation of high value-added and high yield carbon materials via a modified synthetic process. Uniquely, this work put emphasis on the theoretical and experimental investigations of how the biomass properties influence the composition and nanostructure regulation, the electrolyte ion adsorption free energy, and the electrical conductivity of the derived carbon materials as well as their electrochemical performance optimization. Owing to the favorable specific surface area, the hierarchical porous structure, and the diverse elemental distribution, corn cob and corn silk derived carbon materials (CBC and SBC) present great potential as promising electrodes for alkaline aqueous zinc batteries and supercapacitors. The assembled CBC//Zn and SBC//Zn zinc batteries deliver high energy densities of 63.0 Wh kg^-1 and 39.1 Wh kg^-1 at a power density of 575 W kg^-1, with excellent cycling performance of 91.1% and 84.3% capacitance retention after 10,000 cycles. As for the assembled symmetric supercapacitors, high energy densities of 14.9 Wh kg^-1 and 13.6 Wh kg^-1, and superior long-term cycling stability of 99.3% and 96.6% capacitance retention after 20,000 cycles could be achieved. This study highlights the advantages of utilizing corn cob and corn silk as carbon sources on the designed synthesis of carbon electrodes, and presents a meaningful perspective in the investigation of biomass-derived carbon materials and their potential applications in rechargeable devices.

Potential transition and post-transition metal sulfides as efficient electrodes for energy storage applications: review

Electrochemical energy storage has attracted much attention due to the common recognition of sustainable energy development. Transition metal sulfides and post-transition metal sulfides have been intensively been focused on due to their potential as electrode materials for energy storage applications in different types of capacitors such as supercapacitors and pseudocapacitors, which have high power density and long cycle life. Herein, the physicochemical properties of transition and post-transition metal sulfides, their typical synthesis, structural characterization, and electrochemical energy storage applications are reviewed. Various perspectives on the design and fabrication of transition and post-transition metal sulfides-based electrode materials having capacitive applications are discussed. This review further discusses various strategies to develop transition and/or post-transition metal sulfide heterostructured electrode-based self-powered photocapacitors with high energy storage efficiencies.

Electrochemical energy storage has attracted much attention due to the common recognition of sustainable energy development.

The fabrication of flexible wearable electrodes based on a carbon nanotubes/nickel/nickelous hydroxide ternary composite by facile single-side printing technology

A new material design strategy is developed to prepare high-performance flexible electrochemical electrodes. Carbon nanotubes (CNTs) and nickel/nickelous hydroxide (Ni/Ni(OH)₂) are compounded through a chemical plating method and hydrothermal process. A single-side printing method is used to combine the active material and a flexible cotton substrate. The interfinger microstructure of the textile electrode can greatly facilitate charge/ion transfer at the electrode-electrolyte interface. One side of the fabric, which is untreated, could directly contact with human skin, providing a comfortable and user-friendly surface. With the CNTs/Ni/Ni(OH)₂ ternary composite as a positive electrode and CNTs as a negative electrode, we assembled an in-plane asymmetrical micro-supercapacitor device (SF-NPCs). Thanks to a synergistic effect, SF-NPCs displays a high energy density of 0.29 W h cm^-2 at a power density of 7.2 W cm^-2. The operating window is extended to 1.5 V, and the device displays good potential for applications in the field of smart textiles.

Synthesis of zinc sulfide/copper sulfide/porous carbonized cotton nanocomposites for flexible supercapacitor and recyclable photocatalysis with high performance

The composite material composed of zinc sulfide, copper sulfide and porous carbon is prepared in this study, exhibiting excellent performances in the field of supercapacitor electrode and photocatalysts. In the degradation process of organic pollutants, zinc sulfide/copper sulfide with heterostructure effectively reduce the recombination rate of photo-generated electron-hole pairs. And the porous carbon substrate can not only accelerate the separation of photo-carriers but also provide numerous active sites. Furthermore, the sample can be easily separated after decomposing the organic pollutants. As a supercapacitor electrode, the combination of zinc sulfide/copper sulfide with large pseudo-capacitance and porous carbon material with excellent double-layercapacitance results in superior electrochemical performances. The composite electrode shows a high specific capacitance of 1925 mF cm^-2/0.53 mAh cm^-2 at 4 mA cm^-2. And the symmetric flexible supercapacitor based on the composite electrode achieves an outstanding energy density (0.39 Wh cm^-2 at the power density of 4.32 W cm^-2). Therefore, the zinc sulfide/copper sulfide/porous carbonized cotton nanocomposites (pCZCS) prepared herein exhibit dual functions of photocatalysts with high efficiency as well as energy storage materials with high energy density, which is interesting and important for expanding the practical applications in cross fields.