A hydrothermal method was developed to grow ultrathin MoS2 nanosheets, with an expanded spacing of the (002) planes, on carbon nanotubes. When used as a sodium-ion battery anode, the composite exhibited a specific capacity of 495.9 mAh g(-1), and 84.8% of the initial capacity was retained after 80 cycles, even at a current density of 200 mA g(-1). X-ray diffraction analyses show that the sodiation/desodiation mechanismis based on a conversion reaction. The high capacity and long-term stability at a high current ate demonstrate that the composite is a very promising candidate for use as an anode material in sodium-ion batteries.

Nanostructured MoS2 is very promising as an electrocatalyst for hydrogen evolution due to a greater number of active edge sites. However, a very large resistance between basal planes decreases the overall efficiency of hydrogen evolution, and greatly limits its application in industry. Herein we develop a facile strategy to synergistically increase the number of active edge sites and the conductivity of MoS2. MoS2 nanosheet arrays can be grown vertically on a carbon fiber cloth (CFC) substrates by a facile strategy. On the one hand, ammonium fluoride in the reaction system could effectively etch the inert basal plane of the MoS2 nanosheets, leading to the formation of pits in the inert basal plane of the MoS2 nanosheets. Thereby the number of active edge sites is significantly increased. On the other hand, the vertical growth of MoS2 nanosheet arrays on CFCs can significantly decrease the resistance of MoS2-based electrocatalysts. As a result, the MoS2-based electrocatalysts exhibit excellent catalytic activity for hydrogen evolution reactions, with a small Tafel slope and a large cathodic current density. Moreover, the CFC can be repeatedly utilized as a template to grow ultrathin MoS2 nanosheet arrays for HERs. The excellent activity and recyclable utilization, as well as mass production, indicate that the composite has promising applications in industry.

MoSe2 nanosheets with ultrathin thickness and rich defects were grown on the surface of carbon fiber cloth by a facile solvent-thermal method. The active area and conductivity of the MoSe2 catalyst were increased simultaneously because of the NH4F etching effect and its incorporation with carbon fiber cloth. As a result, the MoSe2-based catalysts exhibited excellent HER activity including small onset potential, large exchange current density and small Tafel slope, which is superior to most of MoSe2-based catalysts reported previously.

The composition-tuned, structure-modified, and morphologycontrolled nanoscale metal−organic frameworks (MOFs) are quite important to improve the electrochemical performances for supercapacitors. In this work, a solvent-controlled method to prepare amino-functionalized bimetal MOFs with various morphologies is proposed. Three different morphologies of NiCo-MOFs, such as nanospheres, nanosheet-assembled hollow spheres (NSHSs), and rhombus sheets, have been successfully synthesized by using different solvents. The as-prepared three nanoscale NiCo-MOFs are comparatively characterized and are endowed a possible mechanism on nucleation and crystal growth controlling morphology. When used as electrode materials for supercapacitors, all NiCo-MOFs have excellent electrochemical properties. Specifically, the NiCo-MOF NSHS owns the best specific capacitance, which can achieve 1126.7 F g −1 at the current density of 0.5 A g −1 and maintain 93% of its original capacitance at the current density of 10 A g −1 after 3000 charge− discharge cycles. Moreover, an asymmetric supercapacitor device (NiCo-MOF NSHS//AC) assembled with NiCo-MOF NSHS as the positive electrode and activated carbon (AC) as the negative electrode achieves an energy density of 20.94 Wh kg −1 at a power density of 750.84 W kg −1 . This work is facile and highly reproducible and can be extended to prepare other nano-MOFs in energy storage and conversion fields. In addition, it opens up an effective approach to synthesizing amino-functionalized MOFs by a solventcontrolled method without any other changes in the experimental conditions.