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GeTe as one of the most promising medium temperature thermoelectrics has progressed leaps and bounds in recent years, largely thanks to a combination of its unique electronic, thermal and structural properties. Despite its various advantages, a major factor standing in the way of wide commercial adoptions lies in its unreliable mechanical properties. This work reports Re doping as a strategy to drastically enhance the mechanical properties of GeTe, resulting in Vickers microhardness as high as 342.6 Hv in Ge0.88Sb0.10Re0.02Te, which is more than double that of pristine GeTe (145 Hv). Ge0.88Sb0.10Re0.02Te also exhibited a Young's modulus of 64.1 GPa, substantially higher than many other binary chalcogenide thermoelectrics. The significant enhancement of GeTe in mechanical properties is mainly related to the mechanism of precipitation hardening. In addition, we found that while the electronic properties were slightly compromised with Re doping, the lattice thermal conductivity was reduced due to point defects scattering brought about by Re atoms. Therefore, a high zT value (>1.6) at 600–800 K is achieved in Ge0.88Sb0.10Re0.02Te. Furthermore, above 10% device efficiency can be expected for the operating temperature between 300–800 K. Such a solution to strengthen the mechanical properties of GeTe using Re doping is expected to play a major part in the push for full-scale GeTe-based thermoelectric devices.

Gel polymer electrolytes are an important advancement in energy storage technology due to their enhanced safety and practical ionic conductivities at ambient temperatures. Herein, a simple one-step facile synthesis of chemically crosslinked polyurethanes containing polyethylene oxide (PEO) and polypropylene oxide (PPO) macromolecular segments was developed, using ubiquitous non-toxic tetrabutylammonium or potassium chloride and bromide salts as catalysts. These salts were shown to catalyze the gelation of diol-diisocyanate polyaddition reactions within minutes. When impregnated with a liquid electrolyte, the resulting gel electrolyte exhibited a practical ionic conductivity of 1.1×10-4 S cm-1 at 40 °C and low segmental chain motion activation energy (11 kJ mol-1 ). These findings further promote PEO-PPO polyurethanes as a biocompatible class of materials suitable for further exploration as gel polymer electrolytes for supercapacitors.

We report cobalt sulfide nanoparticles decorated nitrogen and sulfur co-doped graphene nanosheets as an effective bifunctional oxygen catalyst. Its oxygen evolution reaction (OER) catalytic activity outperforms Pt/C, giving a current density of 38.19 mA cm−2 at 1.0 V. Zn–air batteries using this material on air-cathode show high stability and good rechargeability.

Lithium nitrate (LiNO3) is known as an important electrolyte additive in lithium-sulfur (Li-S) batteries. The prevailing understanding is that LiNO3 reacts with metallic lithium anode to form a passivation layer which suppresses redox shuttles of lithium polysulfides, enabling good rechargeability of Li-S batteries. However, this view is seeing more challenges in the recent studies, and above all, the inability of inhibiting polysulfide reduction on Li anode. A closely related issue is the progressive reduction of LiNO3 on Li anode which elevates internal resistance of the cell and compromises its cycling stability. Herein, we systematically investigated the function of LiNO3 in redox-shuttle suppression, and propose the suppression as a result of catalyzed oxidation of polysulfides to sulfur by nitrate anions on or in the proximity of the electrode surface upon cell charging. This hypothesis is supported by both density functional theory calculations and the nitrate anions-suppressed self-discharge rate in Li-S cells. The catalytic mechanism is further validated by the use of ruthenium oxide (RuO2, a good oxygen evolution catalyst) on cathode, which equips the LiNO3-free cell with higher capacity and improved capacity retention over 400 cycles.

Lewis acid/base addition between Pd2(dppf)2(μ-S)2 and MXn [M = In(III), Ga(III), Tl(I), Pb(II), Sn(IV), Bi(III), Ag(I) and Au(I); X = halide or pseudohalide; dppf = 1,1′-bis(diphenylphosphino)ferrocene] gives rise to a range of neutral or cationic intermetallics aggregates with the {Pd2MS2} or {Pd2M2S2} core. Effectively Pd2(dppf)2(μ-S)2 functions as a chelating or bridging dithio metalloligand. Two representative crystal structures, viz. [InPd2Cl3(dppf)2(μ3-S)2] · 3CH2Cl2 and [Ag2Pd2(NO3)2(dppf)2(μ3-S)2] · 2CH2Cl2 are described and discussed. The former features an intermetallic {InPd2} triangle whereas the latter displays a heterometallic {Ag2Pd2} metal plane. Both of them are sustained and supported by capping sulfides without significant or direct metal–metal bonds.

Redox condensation of PPN[Mn2(μ-PPh2)(CO)8] and PdCl2(η2-dppm) gives bimetallic PdMn(μ-PPh2)(μ-dppm)(CO)3(PPh3) (1) with an unexpected formation of PPh3. The latter can be displaced when 1 reacts with free diphosphines (dppm, dppe, dppf) giving PdMn(μ-PPh2)(μ-dppm)(CO)3(Ph2PXP(O)Ph2) (2, XCH2 (2a), C2H4 (2b), C5H4FeC5H4 (2c)) and [PdMn(CO)3(μ-PPh2)(μ-dppm)]2(μ-Ph2PXPPh2) (3a). Complexes 2 are “A-frame”-type bimetallic complexes with an syn-dppm bridging the MnPd bond. In contrast, complex 3a is a “double A-frame” anti-bridged by dppm. As a result, the latter is trans to the MnPd bonds. Both types of dppm bridges are substitutionally inert. Either bridging role is best served by dppm (and not dppe or dppf). The structures of the complexes were derived from NMR analyses of all complexes and X-ray single-crystal diffraction analyses of 1, 2a and 2b. The common and stable “A-frame”-type core in these bimetallics provides a thermodynamic driving force for the opposite transmetallation migration of phosphide and phosphine (dppm) when 1 is formed.

Although catalytically active palladium phosphine carboxylates are generally unstable, a series of such complexes are stabilized by dppf, viz. Pd(O2CR)2(dppf) [R=CF3 I, CF2CF3 II [1] , [43] CF2CF2CF3 III, CHCl2 IV, o-C6H4Cl VI, CH2CO2H VII, CHCHCO2H VIII]. They have been spectroscopically characterized and their structures determined by X-ray single-crystal crystallography. Two derivatives viz. Pd(O4C2-O,O′)(dppf) IX and PdCl(O2CPh)(dppf) X are included for comparison. They are invariably mononuclear with chelating phosphine and unidentate carboxylates. The more labile (and less basic) carboxylates tend to form complexes that are more resistive to reductive decomposition. Pd(O2CPh)2(dppf) V decomposes readily to PdCl2(dppf) in the presence of chlorinated solvents.

The bidentate ligand 1,1’-bis(diphenylphosphino)ferrocene (dppf) is a widely used component in catalytic systems and its role in this capacity has been expertly reviewed elsewhere. The focus of this Perspective is the increasing use of dppf in the synthesis and matrix of 21st century materials. The ferrocene core imparts fine control to catalytic C–C and C–X coupling reactions used to manufacture a range of functional macromolecules from tailored dyes and OLED components to precisely engineered conducting polymers and thermoplastics. This ligand's limited flexibility resembles a ball and socket joint with simultaneous rotation and constrained perpendicular freedom. This uniquely restricted range of movement stabilizes a diverse array of ground and transition states for these important transition metal catalysed coupling reactions. It may also contribute desirable mechanical or electronic functionality as a bridging or chelating component in a coordination array, metallocycle or larger supramolecular assembly. The ferrocene offers steric bulk and crystallinity to these materials aiding chemical stability and ease of handing. It's oxidizability assists characterization and may be tailored to provide or complement photo- or electroactivity. Dppf containing materials have been designed with diverse functions from cooperative luminescence to host–guest complexation. It is likely that this ubiquitous lab companion will increasingly find its way into the fabric or processing of future functional molecular materials.

This Review describes an important subclass of N-heterocyclic carbene complexes with thiazol-2-ylidenes ligands with only one exocyclic substituent on the thiazole ring. It highlights the synthetic, structural, and catalytic properties of these rapidly emerging complexes.

The bidentate ligand 1,1'-bis(diphenylphosphino)ferrocene (dppf) is a widely used component in catalytic systems and its role in this capacity has been expertly reviewed elsewhere. The focus of this Perspective is the increasing use of dppf in the synthesis and matrix of 21st century materials. The ferrocene core imparts fine control to catalytic C-C and C-X coupling reactions used to manufacture a range of functional macromolecules from tailored dyes and OLED components to precisely engineered conducting polymers and thermoplastics. This ligand's limited flexibility resembles a ball and socket joint with simultaneous rotation and constrained perpendicular freedom. This uniquely restricted range of movement stabilizes a diverse array of ground and transition states for these important transition metal catalysed coupling reactions. It may also contribute desirable mechanical or electronic functionality as a bridging or chelating component in a coordination array, metallocycle or larger supramolecular assembly. The ferrocene offers steric bulk and crystallinity to these materials aiding chemical stability and ease of handing. It's oxidizability assists characterization and may be tailored to provide or complement photo- or electroactivity. Dppf containing materials have been designed with diverse functions from cooperative luminescence to host-guest complexation. It is likely that this ubiquitous lab companion will increasingly find its way into the fabric or processing of future functional molecular materials.

This Review describes an important subclass of N-heterocyclic carbene complexes with thiazol-2-ylidenes ligands with only one exocyclic substituent on the thiazole ring. It highlights the synthetic, structural, and catalytic properties of these rapidly emerging complexes.