One step hydrothermal synthesis of 3D CoS2@MoS2-NG for high performance supercapacitors

Low-dimensional transition metal sulfide-based electrocatalysts for water electrolysis: overview and perspectives

Hydrogen prepared by electrocatalytic decomposition of water ("green hydrogen") has the advantages of high energy density and being clean and pollution-free, which is an important energy carrier to face the problems of the energy crisis and environmental pollution. However, the most used commercial electrocatalysts are based on expensive and scarce precious metals and their alloy materials, which seriously restricts the large-scale industrial application of hydrogen energy. The development of efficient non-precious metal electrocatalysts is the key to achieving the sustainable development of the hydrogen energy industry. Transition metal sulfides (TMS) have become popular non-precious metal electrocatalysts with great application potential due to their large specific surface area, unique electronic structure, and rich regulatory strategies. To further improve their catalytic activities for practical application, many methods have been tried in recent years, including control of morphology and crystal plane, metal/nonmetal doping, vacancy engineering, building of self-supporting electrocatalysts, interface engineering, etc. In this review, we introduce firstly the common types of TMS and their preparation. Additionally, we summarize the recent developments of the many different strategies mentioned above for efficient water electrolysis applications. Furthermore, the rationales behind their enhanced electrochemical performances are discussed. Lastly, the challenges and future perspectives are briefly discussed for TMS-based water dissociation catalysts.

One-Step Hydrothermal Synthesis of MoO2/MoS2 Nanocomposites as High-Performance Electrode Material for Supercapacitors

By only changing the ratio of Mo to S source, a distinctive single phase MoO2 or MoS2 and MoO2/MoS2 nanocomposites (NCs) are obtained through a simple one-step hydrothermal method based on CH4N2S as a sulfur source and (NH4)6Mo7O24·4H2O as a source of Mo in oxalic acid. The effect of ratio of Mo to S source on the composition, structure, and electrochemical performance are systematically researched. Due to its unique design, abundant macropores active sites in MoO2/MoS2 NCs induce superior rate property (55.30% capacitance retention to 20 from 1 A g-1) and larger specific capacitance (1667.3 F g-1 at 1 A g-1) and longer cycle life (94.75% after 5000 cycles) as used directly as an electrode. Furthermore, at a power density of 225 W kg-1, a maximal energy density of 21.85 Wh kg-1 is provided by the asymmetric supercapacitor (MoO2/MoS2//AC). The capacitance of asymmetric supercapacitor (ASC) is remarkably enhanced by 129.02% under 5000 cycles at a current density of 1.5 A g-1, demonstrating outstanding cycle property. These results imply the prepared MoO2/MoS2 NCs have promising applications in advanced energy storages. It is important and should be noted that NCs of oxide and sulfide are prepared with only a simple one-step process.

Binary mixed molybdenum cobalt sulfide nanosheets decorated on rGO as a high-performance supercapacitor electrode

This work represents the production of MoS₂/CoS₂ hybridized with rGO as a material for high-performance supercapacitors. The hydrothermal method is used for the synthesis. The as-prepared material is characterized by x-ray diffraction spectroscopy, x-ray photoelectron spectroscopy, and electron microscopy. The size of the nanoparticles is estimated at 80 nm, and their uniform dispersion on rGO is observed from electron microscopy images. A high-specific capacitance of 190 mF cm^-2 obtains for MoS₂/CoS₂/rGO at the current density of 0.5 mA cm^-2 in 2 M KOH. The cyclic stability over 5000 cycles at a scan rate of 100 mV s^-1 shows that the MoS₂/CoS₂/rGO electrode is stable, and 88.6% of its initial capacitance sustains at the end of 5000 cycles. This excellent performance is assigned to the synergistic effect of rGO and MoS₂/CoS₂. This electrode with excellent stability and capacitance could be a potential candidate for supercapacitor electrode materials.

Konjac glucomannan-derived nitrogen-containing layered microporous carbon for high-performance supercapacitors

Biomass-derived carbon-based materials represent a promising class of candidates for supercapacitors.

One-step synthesis of nitrogen-doped wood derived carbons as advanced electrodes for supercapacitor applications

Nitrogen-doped wood derived carbon was first prepared by a one-step method without destroying the original hierarchical porous structure of wood.