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Moreover, the cross-plane thermal resistance decreases monotonically with temperature and coupling strength, and can be modulated by external strain. Surprisingly, the cross-plane tensile strain can reduce the thermal resistance of the heptazine-based GCN. Our study serves as a guide to groups interested in the physical properties of GCN.The currently emerging sodium-ion battery technology is in need of an optimized standard organic solvent electrolyte based on solid and directly comparable data. With this aim we have made a systematic study of "simple" electrolyte systems consisting of two sodium salts (NaTFSI and NaPF6) dissolved in three different alkyl carbonate solvents (EC, PC, DMC) within a wide range of salt concentrations and investigated (i) their more macroscopic physico-chemical properties such as ionic conductivity, viscosity, thermal stability, and (ii) the molecular level properties such as ion-pairing and solvation. From this all electrolytes were found to have useful thermal operational windows and electrochemical stability windows, allowing for large scale energy storage technologies focused on load levelling or (to a less extent) electric vehicles, and ionic conductivities on par with analogous lithium-ion battery electrolytes, giving promise to also be power performant. Furthermore, at the molecular level the NaPF6-based electrolytes are more dissociated than the NaTFSI-based ones because of the higher ionic association strength of TFSI compared to PF6- while two different conformers of DMC participate in the Na+ first solvation shells - a Na+ affected conformational equilibrium and induced polarity of DMC. The non-negligible presence of DMC in the Na+ first solvation shells increases as a function of salt concentration. Overall, these results should both have a general impact on the design of more performant Na-conducting electrolytes and provide useful insight on the very details of the importance of DMC conformers in any cation solvation studies.In the present work, the influence of Ag-induced plasmons on the surface optical (SO) phonon modes of NiO nanoparticles was extensively studied using room temperature Raman spectroscopy. Remarkable intensity enhancements were observed for the rarely reported SO phonon modes compared to the other first-order phonon modes of NiO nanoparticles. The occurrence of SO modes was further studied using an approximate dielectric continuum (DC) model and a difference between the calculated and experimental SO frequencies was observed, which can be attributed to the presence of one magnon background over the first order phonon modes. The experimental and theoretical SO frequencies became closer at higher Ag concentration and the second-order magnon (2M) and phonon bands disappeared in the NiOAg samples. The absence of magnon and higher order phonon modes in the NiOAg samples indicates changes in the magnetic properties of the nanomaterials, which has been further supported by the vibrating-sample magnetometer (VSM) measurements.Reorientation of organic cations in the cubic interstices of cyanoelpasolite molecular perovskites results in a variety of structural phase transitions, but far less is known about these cations' dynamics. We report quasielastic neutron scattering from the materials (C3H5N2)2K[MIII(CN)6], M = Fe,Co, which is directly sensitive to the rotation of the imidazolium ion. The motion is well described by a circular three-site hopping model, with the ion rotating within its plane in the intermediate-temperature phase, but tilting permanently in the high-temperature phase. Thus the two rhombohedral phases, which are crystallographically rather similar, have markedly different dynamics. The activation energy of rotation is about 10 kJ mol-1 and the barrier between orientations is 6 kJ mol-1. Our results explain two anomalous features in these materials' dielectric constants.Molecular dynamics (MD) is a powerful tool to investigate microscopic transport of atoms and molecules in condensed matter. However, there lies a large class of systems wherein atomic diffusion is too slow a process relative to the feasible time scales of typical atomistic simulations. Here, we demonstrate that with judicial implementation of a metadynamics (MTD) technique, the microscopic mechanism of atomic transport in solids can be accessed within a reasonable computational time. The calculations are carried out on the two end members of the true NASICON solid solutions, namely NaZr2(PO4)3 and Na4Zr2(SiO4)3, wherein Na+ diffusion is too slow to be accessed through standard MD simulations. The study also provides fresh insights on correlated ion hops and their implications on the effective diffusion barrier. The results are compared with climbing image nudged elastic band (CI-NEB) calculation, and available experimental results.Accelerated rate calorimetric studies have been employed to study the exothermic and thermal runaway behaviour of some aprotic and protic ionic liquids based on several families of ions including the bis(flurorsulfonyl)imide anion ([FSI]-); it was found that the protic salts are safer than aprotic salts of the [FSI]- anion.Hollow nanospheres are desirable to resolve the volume expansion of red phosphorus anodes for sodium-ion batteries. Here, we developed a mild molten salt method to prepare hollow red phosphorus in the NaCl-KCl-AlCl3 system by using the Kirkendall effect. As an anode for sodium-ion batteries, the prepared hollow nanospheres exhibit a highly reversible capacity of 624 mA h g-1 at 4.0C and 737 mA h g-1 at 1.0C even after 600 cycles with a low capacity fading rate of 0.06% per cycle.Molecular martensitic materials are an emerging class of smart materials with enormous tunability in physicochemical properties, attributed to the tailored molecular and crystal structures through molecular design. This class of materials exhibits ultrafast and reversible structural transitions in response to thermal and mechanical stimuli, which underlies fascinating properties such as thermoelasticity, superelasticity, ferroelasticity, and shape memory effect. These dynamic properties are not widely explored in molecular crystals and therefore molecular martensitic materials represent a new frontier in the field of solid-state chemistry. In martensitic transitions, the materials not only exhibit substantial shape changes but also remember the functions in the associated polymorphic phases. This suggests promising applicability towards light-weight actuators, lifts, dampers, sensors, shape-/function-memory and ultraflexible optoelectronic devices. see more In this article, we review characteristics, detailed transition mechanisms, and potential applications of molecular martensitic materials. In particular, we aim to describe transition characteristics by collecting cases with similar transition principles in order to glean insights into further advancement of molecular martensitic materials. Overall, we believe that molecular martensitic materials are emerging as the next generation smart materials that have shown promise in advancing a wide range of domains of applications.The design and characterization of the heteronuclear group 14 C[triple bond, length as m-dash]E (E = Si, Ge, Sn, Pb) triple bonds have attracted intensive interest in the past few decades. In the current work, utilizing the advantages of N-heterocyclic carbenes (NHCs) and Lewis acid-base pair strategy, we theoretically designed a new class of compounds III-1, i.e., (NHCAR)C[triple bond, length as m-dash]E(Al(C6F5)3). Quantum chemical calculations showed that these singlet compounds possess very favourable isomerization, fragmentation and dimerization stabilities at the B3LYP/def2-TZVPP//B3LYP/def2-SVP level. The calculated bond lengths of CE in III-1 are 1.63 Å for Si, 1.70 Å for Ge, 1.91 Å for Sn and 2.01 Å for Pb, respectively, which are close to or even shorter than the known C[triple bond, length as m-dash]E bond lengths. In addition, the significant Mayer bond order values, two orthogonal π orbitals and one σ orbital between the C and E atoms also indicate the characteristics of triple bonds. Based on several bonding analyses, strong delocalization is found to exist between the C[triple bond, length as m-dash]E core and NHCAR forming a weak C[double bond, length as m-dash]C double bond. Hence, such obtained C[triple bond, length as m-dash]E species also can be described by their resonace structures as cunmulene analogs. In all, III-1 proposed here not only presents a universal C[triple bond, length as m-dash]E motif for all the heavier group 14 elements, but also provides a new strategy for the design and synthesis of heteronuclear group 14 triple bonds in the future.The classical trajectory method in a quantum spirit assigns statistical weights to classical paths on the basis of two semiclassical corrections Gaussian binning and the adiabaticity correction. This approach was recently applied to the heterogeneous gas-surface reaction between H2 in its internal ground state and Pd(111) surface e.g. [A. Rodríguez-Fernández et al., J. Phys. Chem. Lett., 2019, 10, 7629]. Its predictions of the sticking and state-resolved reflection probabilities were found to be in surprisingly good agreement with those of exact quantum time-dependent calculations where standard quasi-classical trajectory calculations failed. We show in this work that the quality of the previous calculations is maintained or even improved when H2 is rotationally excited.The n-type hexagonal (Bi(Bi2S3)9)I3)0.667 compound was synthesized by a facile process, a hydrothermal method combined with spark plasma sintering. The thermoelectric properties of the (Bi(Bi2S3)9)I3)0.667 bulk sample were investigated in detail. The results show that a peak ZT value of 0.04 was obtained at 673 K along the perpendicular pressure direction.The design of molecular rotors that can rotate at ultrahigh speeds is important for the development of artificial molecular machines. Based on theoretical calculations, we demonstrate that two kinds of carbon nano-rings, i.e. [n]cycloparaphenylenes ([n]CPP) and cyclo[18]carbon (C18), can form an ultrafast ring-in-ring nano-rotor through π-π interaction. As a high-symmetry and low-barrier rotator, the rotational frequency of C18 in [11]CPP is close to the THz regime. At low temperatures, the motion of the [11]CPPC18 system is purely rotational. As temperature increases, precession movements start to be observed and the motion resembles the behaviour of a gyroscope. The [11]CPPC18 rotor can serve as a building block for bottom-up construction of more complex molecular machines.We present a novel fuel cell heterogeneous catalyst based on rhodium, nickel and sulfur with power densities 5-28% that of platinum. The NiRhS heterogeneous catalyst was developed via a homogeneous model complex of the [NiFe]hydrogenases (H2ases) and can act as both the cathode and anode of a fuel cell.Herein, we investigate the electrochemical properties of a class of Supramolecular Self-associated Amphiphilic salts (SSAs). We show that varying ionic strength of an SSA solution can cause a switching of the thermodynamics and kinetics of electron transfer. The effect of self-assembly on proton-coupled electron transfer has implications for the understanding of electron transfer kinetics in aqueous organic redox flow batteries, especially at high concentration where organic-organic intermolecular interactions become dominant even for highly soluble organic species.