Design of pyrite/carbon nanospheres as high-capacity cathode for lithium-ion batteries

Transition metal sulfides are emerging as promising electrode materials for energy storage and conversion.In this work,hierarchical FeS2/C nanospheres are synthesized through a controllable solvothermal method followed by the annealing process.Spherical FeS2 core is homogeneously coated by thin carbon shell.The hierarchical nanostructure and carbon coating can enhance electron transfer and accommodate the stress originated from the volume change as well as suppress the shuttle effect of polysulfide.Consequently,as the cathode material of lithium ion batteries(LIBs),the FeS2/C nanospheres exhibit high reversible capacity of 676 m Ahg^-1 and excellent cycling life with the capacity retention of 97.1%after100 cycles.In addition,even at the high current density of 1.8 C,a reversible capacity of 437 m Ahg^-1 is obtained for the FeS2/C nanospheres,demonstrating its great prospect for practical applications in highperformance LIBs.

Mn-Based Two Dimensional Metal-Organic Framework Material from Benzimidazole-5,6-dicarboxylic Acid

A new two-dimensional metal-organic framework （MOF） structure has been synthesized by mild solvothermal reaction of MnC12o4H20 with 1H-benzimidazole-5,6-dicarboxylic acid （H3bidc） at 85℃. The structure has been characterized by single-crystal X-ray diffraction, powder X-ray diffraction （PXRD）, infrared spectroscopy （FT-IR）, and thermogravimetric analysis （TGA）. Single-crystal X-ray diffraction analysis revealed that this MOF is a five-coordinated Mn（II） compound exhibiting a layered 2D network, in which the hydrogen-bonding interactions between uncoordinated carboxylic oxygen atoms and N--H groups in the imidazole rings play a key role in the fi- nal 3D supramolecular architecture. This MOF shows high thermal stability up to 400℃. Furthermore, XRD pattern of the MOF structure was retained for up to 20 d after soaked in water, and only 2.8 wt% of the MOF was decomposed within the first 48 h in water.

A New Microporous Metal-Organic Framework for Highly Selective C2H2/CH4 and C2H2/CO2 Separation at Room Temperature

We have successfully designed and synthesized a new tetracarboxylic linker, which constructed its first three-dimensional microporous metal-organic framework （MOF）, [Cu2（DDPD）（H2O）2]·Gx （ZJU-13, H4DDPD= 5,5＇-（2,6-dihydroxynaphthalene-1,5-diyl）diisophthalic acid, ZJU=Zhejiang University, G=guest molecules） via solvothermal reaction. Due to open Cu^2＋ sites and optimized pore size, the activated ZJU-13a displays high separation selectivity for CzH2/CH4 of 74 and C2H2/CO2 of 12.5 at low pressure by using Ideal Adsorbed Solution Theory （IAST） simulation at room temperature.

Metal-Anion Coordination and Linker-Anion Hydrogen Bonding in the Construction of Metal-Organic Frameworks from Bipyrazole

Two new two-dimensional frameworks based on packing of square grids, Cu（Me4bpz）2（NO3）2 （1） and Zn（Me4bpz）（SO4） （2） （Me4bpz=3,Y,5,5＇-tetramethyl-4,4＇-bipyrazole）, have been synthesized by mild solvothermal method. In addition to the major metal-organic linker coordination, they allow us to study how the metal-inorganic anion coordination and organic linker-inorganic anion hydrogen bonding affect the resulting structures during the framework assembly.