Carbon nanotube (CNT) current collectors with excellent fl exibility, extremely low density (0.04 mg cm − 2 ), and tunable thickness are fabricated by crossstacking continuous CNT fi lms drawn from super-aligned CNT arrays. Compared with metal current collectors, better wetting, stronger adhesion, greater mechanical durability, and lower contact resistance are demonstrated at the electrode/CNT interface. Electrodes with CNT current collectors show improvements in cycling stability, rate capability, and gravimetric energy density over those with metal current collectors. These results suggest that CNT fi lms can function as a promising type of current collector for lightweight and fl exible lithium ion batteries with high energy density.

Monodisperse lanthanide oxysulfide nanoplates and short nanorods were synthesized by the thermal decomposition of molecular precursors in the presence of oxygen. The nanoplates have uniform thicknesses and further self-organize to nanowires up to micron scale. The Eu2O2S and Eu3+-doped Gd2O2S nanocrystals both show unusual fluorescence properties obviously differing from the bulk powder phosphors, which are related to the surface-modification effects.

Nickel‐rich layered transition‐metal oxides with high‐capacity and high‐power capabilities are established as the principal cathode candidates for next‐generation lithium‐ion batteries. However, several intractable issues such as the poor thermal stability and rapid capacity fade as well as the air‐sensitivity particularly for the Ni content over 80% have seriously restricted their broadly practical applications. The properties and nature of the stable surface/interface, where the Li+ shuttles back and forth between the cathode and electrolyte, play a significant role in their ultimate lithium‐storage performance and industrial processability. Thus, tremendous efforts are made to in‐depth understanding of the essential origins of surface/interface structure degradation and efficient surface modification methodologies are intensively explored. The purpose of the contribution is first to provide a comprehensive review of the up‐to‐date mechanisms proposed to rationally elucidate the surface/interface behaviors, and then, focus on recent developed strategies to optimize the surface/interface structure and chemistry including synthetic condition regulation, surface doping, surface coating, dual doping‐coating modification, and concentration‐gradient structure as well as electrolyte additives. Finally, the perspective on future research trends and feasible approaches toward advanced Ni‐rich cathodes with stable surface/interface is presented briefly.

Size-controllable monodisperse nanomaterials have been studied intensively due to their fundamental scientific interest and potential technological applications. [1] So far, the monodisperse magnetic nanocrystals, such as Fe, Co, FePt, CoPt, Fe 2 O 3 , Fe 3 O 4 , have been synthesized [2] for possible applications in magnetic data storage, ferrofluids, refrigeration systems, medical imaging, drug targeting, and catalysis. [3] Compared with a number of works done on these nanomagnetic metals and metal oxides, sparse work on the preparation and magnetic properties of nanoscale magnetic metallic sulfides has been reported so far. The europium monochalcogenides, EuX (X = O, S, Se, Te), with the rock-salt structure have been studied extensively since the 1960s. The pure, bulk EuO and EuS crystals, whose Curie temperatures (T C ) are 69 and 16.6 K, respectively, are well known to be insulating ferromagnets, in which the Heisenberg model applies. [4] Owing to their wide range of potential applications, such as ferromagnetic semiconductors and magnetoresistance, optomagnetic, and luminescent materials, [4,5] renewed attention has been given to the synthesis and properties of EuO and EuS crystals in the past number of decades. In an earlier study, we synthesized magnetic EuS nanoparticles with an average size of 5.5 nm, [5e] but until now little work on the size-controllable synthesis of monodisperse EuS nanocrystals has been reported. Herein, we report a direct and facile method to synthesize monodisperse EuS nanocrystals with sizes ranging from 2.6 to 20 nm. The EuS nanoparticles were prepared by the thermal decomposition of molecular precursors [Eu(phen)(ddtc) 3 ] and [Eu(bpy)-(ddtc) 3 ] (phen = 1,10-phenanthroline; bpy = 2,2'-pyridine; ddtc = diethyldithiocarbamate), in a way similar to previous work. [5d, e] The as-synthesized nanocrystals have been found to show uniform sizes and could be self-assembled into twodimensional (2D) or three-dimensional (3D) ordered superlattices. It is known that the decrease of the crystal size usually affects the properties of magnetic materials, as the small size usually gives rise to new surfaces, which result in a possible quantum tunneling effect and interparticle interactions. [6] The magnetic behavior of monodisperse EuS nanocrystals with controllable particle sizes was investigated. The magnetic properties were observed to depend strongly on particle size, as found in other nanoscale magnetic materials. [7] These results are interesting and helpful for the synthesis of lanthanide sulfides and in systematically understanding the relationship between size and magnetic properties of nanoscale ferromagnetic samples. On the other hand, a better understanding of the size-dependent properties of magnetic nanoparticles will be helpful to elucidate magnetizing mechanisms and to facilitate the design of magnetic materials.The single molecular precursor was prepared in the way reported by Formanovskii et al. [8] with slight modifications (see Supporting Information). The analysis res...

No abstract

By changing ancillary tetradentate Schiff base ligands (L), two new one-dimensional azide-bridged manganese(III) coordination complexes [MnIII(L)(mu1,3-N3)]n [L = 5-Fsalen (1), 5-OCH3 (2); salen = N,N'-bis(salicylidene)-1,2-diaminoethane] as well as a mononuclear complex [MnIII(salophen)(N3)] (3) [salophen = N,N'-bis(salicylidene)-o-phenylenediamine] have been successfully obtained. All of them have been structurally and magnetically characterized. In the structures of 1-3 each MnIII ion is in a distorted octahedral geometry with an obvious Jahn-Teller effect, where the tetradentate L ligands all bind in the equatorial mode, whereas in the axial direction, the N3- ion acts as an end-to-end bridge in 1 and 2 while a terminal group in 3 with a methanol molecule at the other end. Magnetic characterization shows that the mu1,3-bridging azide ion proves to mainly transmit antiferromagnetic interaction between MnIII ions, but these three complexes exhibit various magnetic behaviors at low temperatures. Noteworthily, complex 2 behaves as a weak ferromagnet with a relatively large coercive field of 2.3 kOe, much larger than the value reported previously.

The copper(II) complexes of the Schiff‐base ligands H2Sams and H2Saes and the reduced Schiff‐base ligands H2Sam and H2Sae formed between salicylaldehyde and aminomethanesulfonic acid or 2‐aminoethanesulfonic acid (taurine) have been synthesized in moderate yields. The solid‐statestructures of the five dinuclear complexes, [Cu2(Sams)2(H2O)2](1), [Cu2(Sam)2(H2O)2]·H2O (2), [Cu2(Saes)2(H2O)2]·2H2O (3), [Cu2(Sae)2]·2H2O (4), and [Cu2(Sae)2(DMF)2]·2DMF (5), have been determined by X‐ray crystallography, showing that the CuII centers have distorted square‐pyramidal geometry. The Schiff‐base copper complexes 1 and 3 have hydrogen‐bonded 2D sheet structures while the reduced Schiff‐base complexes 4 and 5 display a 2D coordination network and a hydrogen‐bonded 2D structure respectively. All these complexes have been investigated for their catecholase activity and activity measurements have been compared with those of dinuclear copper(II) complexes of similar ligands obtained with carboxylate analogues of the corresponding sulfonicacids; these studies show that 4 has significantly higher activity. Further, a strong antiferromagnetic interaction between CuII ions in dimeric complexes 1 [J = –9.04(2) cm–1], 3 [J = –272(4) cm–1), and 4 [J = –237(4) cm–1] has been observed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

2-(2H-Tetrazol-5-yl)-1,10-phenanthroline (HL0), its alkyl-substituted derivatives (Ln, where n = 1-8, 10, 12, 14, and 16, denoting the carbon atom number of the alkyl chain) at the 2H position of the tetrazole ring, and their iron(II) complexes (a for [Fe(L0)2], na for [Fe(Ln)2](ClO4)2, and nb for [Fe(Ln)2](BF4)2) were synthesized and characterized. The crystal structures of a, a.CH3OH, 1a.CH3OH, 1b.CH3OH.CH3CN, 2a.H2O, 2b.H2O, 4b.CH3OH, 5a.H2O, 5b.H2O, 6a, 6b, 7a, 7b, and 16a are described, along with thermal analyses. a undergoes an abrupt spin crossover (SCO) at 255 K with a hysteresis loop of 6 K. a.CH3OH, 2a.H2O, and 2b.H2O exhibit irreversible SCO behaviors due to the loss of solvent molecules upon heating. 3a, 3b, 4a, and 5a.H2O show simple spin transitions above 350 K. The desolvated samples of 4b.CH3OH and 5b.H2O undergo two-step spin transitions. 16a exhibits a two-step SCO behavior between 100 and 300 K, corresponding to sequential phase transitions from the low-spin (LS) phase to the intermediate phase and then to the high-spin phase, respectively, proved by crystal structure analysis and 57Fe Mössbauer spectroscopy. 1a.CH3OH, 10a, 10b, 12a, 12b, 14a, 14b, and 16b show gradual and incomplete SCO behaviors after cooling down from 400 K. 1b.CH3OH.CH3CN, 6a, 6b, 7a, 7b, 8a, and 8b remain in the LS state even at 400 K. This proves that the alkyl side chains, together with the solvent molecules and anions, play a crucial role in the complicated SCO behaviors in this system.