Sulfurized polyacrylonitrile as cathodes for advanced lithium-sulfur batteries: advances in modification strategies.

Sulfurized polyacrylonitrile (S@PAN) composites have gathered a lot of interest because of their advantages of high theoretical energy density, excellent cycling stability, and environmental friendliness. Meanwhile, their unique "covalent bonding" mechanism effectively avoids the dissolution and shuttling of polysulfides, and thus they are expected to be the most promising candidate for the cathode material in lithium-sulfur (Li-S) batteries. Over the past five years, S@PAN cathode materials have been widely studied in Li-S batteries, and it is very important to summarize the advances over time for their practical applications. This article reviews the latest progress concerning the modification of S@PAN cathode materials for improving poor electrical conductivity, low sulfur content, and sluggish reaction kinetics, and proposes possible research directions. We hope this review provides valuable insights and references for future research on Li-S batteries.

Welding Characteristics of Laser-MIG Hybrid Welding of Arc-Welded Aluminum Profiles for High-Speed Trains.

To expand the application of laser-MIG hybrid welding in the arc-welded aluminum alloy profile manufacturing for high-speed trains, the laser-MIG hybrid welding characteristics of 4 mm thick A6N01S-T5 arc-welded aluminum profiles were studied in this work. The welding parameters were optimized using the orthogonal test; the microstructure and properties of the joints were analyzed. The results showed that the optimal welding parameters were: welding speed 1.0 m/min, laser power 2.7 kW, arc current 200 A, spot diameter 0.8 mm, heat source distance 3 mm, and defocusing amount 0 mm. The columnar crystals and dense dendrites were observed near the fusion line and in the weld center, respectively, and the grains in the heat-affected zone were slightly coarse. The microhardness of the softening zone in the heat-affected zone was the lowest. The average tensile strength of the joints was 212 MPa, about 86% of the base metal. The samples fractured in the heat-affected zone, and the fractures showed typical plastic fracture characteristics. The results showed that laser-MIG hybrid welding has good applicability and feasibility for the arc-welded profile welding manufacturing.

Degradation of tri(2-chloroethyl)phosphate by a microwave enhanced heterogeneous Fenton process using iron oxide containing waste.

Iron oxide containing waste was first used in the microwave (MW) enhanced heterogeneous Fenton process for removing tri(2-chloroethyl)phosphate (TCEP) in aqueous solution. The operational parameters that affect the removal efficiency were investigated in detail. Comparing with the traditional Fenton-like reaction and heating assisted Fenton-like reaction, the MW enhanced heterogeneous Fenton process displayed superior treatment efficiency. The iron ore tailing can be reused eight times without significant decrease of catalytic efficiency. The major intermediates were identified and the possible degradation pathways of TCEP were proposed. The acute toxicity gradually decreased during the degradation process and the removal of TOC was 98.8% after 35 min reaction. This study could not only apply the waste tailing as a secondary resource to avoid the tedious preparation of the catalyst, but also proposes a rapid, low-cost and effective alternative method for the removal of polluted water containing TCEP.

Triaqua[2,2'-(propane-1,3-diyl)bis(5-carboxy-1H-imidazole-4-carboxylato-κ(2)N(3),O(4))]calcium(II) tetrahydrate.

In the title compound, [Ca(C(13)H(10)N(4)O(8))(H(2)O)(3)]·4H(2)O, the Ca(II) ion is hepta-coordinated by two N atoms and two O atoms from a tetra-dentate 1,3-bis-(1H-imidazole-4,5-dicarb-oxy-l-ate) propane dianion and three water O atoms, giving a distorted penta-gonal-bipyramidal coordination environment. The Ca-O bond lengths are in the range 2.354 (3)-2.453 (2) Å, while the Ca-N bond lengths are in the range 2.523 (2)-2.548 (2) Å. An intra-molecular O-H⋯O hydrogen bond between the carb-oxy and carboxyl-ate groups stabilizes the mol-ecular configuration. A three-dimensional network of N-H⋯O and O-H⋯O hydrogen bonds help to stabilize the crystal packing.

N-(Quinolin-8-yl)ferrocene-1-carbox-amide.

In the title compound, [Fe(C(5)H(5))(C(15)H(11)N(2)O)], the cyclo-penta-dienyl rings are essentially eclipsed, and the dihedral angle between the cyclo-penta-dienyl ring planes is 0.632 (10)°. The Fe atom is slightly closer to the substituted cyclo-penta-dienyl ring, with an Fe-centroid distance of 1.6374 (3) Š[1.6494 (3) Šfor the unsubstituted ring]. The amide group is essentially coplanar with the substituted cyclo-penta-dienyl ring, with an N-C(O)-C-C torsion angle of 2.3 (3)°.

trans-Diaqua-bis-[5-carb-oxy-4-carboxyl-ato-2-(4-pyridinio)-1H-imidazol-1-ido-κN,O]zinc(II).

In the title complex, [Zn(C(10)H(6)N(3)O(4))(2)(H(2)O)(2)], the Zn(II) atom is located on a twofold rotation axis and is coordinated by two trans-positioned N,O-bidentate and zwitterionic 5-carb-oxy-4-carboxyl-ato-2-(4-pyridinio)-1H-imidazol-1-ide (H(2)PIDC(-)) ligands and two water mol-ecules, defining a distorted octa-hedral environment. The complete solid-state structure can be described as a three-dimensional supra-molecular framework, stabilized by extensive hydrogen-bonding inter-actions involving the coordinated water mol-ecules, uncoordin-ated imidazole N atom, protonated pyridine N and carboxyl-ate O atoms of the H(2)PIDC(-) ligands.