Chemphyschem最新文献

A lithium-metal battery's electrochemical performance is affected by the kinetics of desolvation and ion transport at low temperatures. Here, we propose a low-temperature lithium-metal battery electrolyte. 1,2-Dimethoxyethane (DME) is used as the solvent, 2H,3H-decafluoropentane (HFC) as the diluent, and a high concentration of lithium bis(fluorosulfonyl)imide (LiFSI) as the solute. The addition of HFC diluent increases the number of anions bound to lithium ions and decreases the number of solvents in the solvation structure, which is conducive to the desolvation process at low temperatures. In addition, the anion-dominated solvation structure is conducive to the formation of an inorganic rich solid electrolyte interface (SEI), which effectively enhances the compatibility of LHCE-HFC electrolyte with lithium metal. The LHCE-HFC achieves ultra-high coulombic efficiency of lithium metal anode in Li||Cu batteries (99.31 %) and Li||Li batteries (1080 h) that have strong fluorine content in the interface. The Li||LiFePO₄ (LFP) cells provide a discharge-specific capacity of 92.1 mAh g^-1 at 0.2 C at -20 °C and capacity retention of 89.6 % after 200 cycles.

The Cover Feature illustrates a kesterite (CZTS)-based multilayer photocathode for NH₃ photosynthesis through N₂ reduction. The CZTS, CdS, and TiO₂ layers work synergistically to capture sunlight and drive the reaction. Pt nanoparticles on TiO₂ enhance catalysis, visualized as dynamic molecular interactions. The lush green background symbolizes sustainability, while the solar panel emphasizes renewable energy integration for NH₃ production, aligning research on efficient photocatalytic systems. More information can be found in the Research Article by J. Ferreira de Brito and co-workers (DOI: 10.1002/cphc.202400737).

The Front Cover shows light interacting with a rhodopsin protein in the eye. Upon photoabsorption, the retinal chromophore inside the protein isomerizes. The impact of the protein environment on the active vibrations of the retinal chromophore during photoabsorption is still not well understood. In their Research Article (DOI: 10.1002/cphc.202400878), L. H. Andersen and co-workers examine an unperturbed retinal in vacuo at cryogenic temperature, measuring excited-state coherent oscillations by time-resolved action spectroscopy.

The full-potential linearized augmented plane wave (FP-LAPW) method within the framework of density functional theory (DFT) and semi-classical Boltzmann transport theory under the constant relaxation time approximation has been employed to investigate the structural, mechanical, optoelectronic and thermoelectric properties of novel half-Heusler (HH) ZrYAu alloys (where Y=B or Al) with a valence electron count (VEC) of 8. Our results indicate that both compounds are mechanically stable in structure Type 1 and possess negative formation energies. Additionally, ZrBAu and ZrAlAu display semiconducting behavior, with ZrBAu showing a direct band gap, 0.753 eV (0.774 eV) at point Γ→X and ZrAlAu exhibiting an indirect band gap, 0.431 eV (0.482 eV) at point Γ→Γ, using the generalized gradient approximation (GGA) and Modified Becke and Johnson-generalized gradient approximation (mBJ-GGA), respectively. Based on optical properties, both ZrBAu and ZrAlAu exhibit high optical conductivity within the visible spectrum. In terms of visible light absorption, ZrBAu primarily absorbs blue light, while ZrAlAu absorbs yellow, blue-green and violet light. However, both compounds are effective absorbers of UV light. Regarding thermoelectric performance, the thermoelectric parameters reveal that ZrBAu and ZrAlAu demonstrate significant p-type thermoelectric power. These half-Heusler alloys have a high-power factor, making them promising candidates for thermoelectric applications.

This study investigates the relaxation mechanisms of pyrrole and pyrrole-water clusters (C₄H₅N-(H₂O)_n, where $n=0-3$ ) following N-2s ionization of pyrrole. Using various theoretical methods, we focus on the influence of water molecules and charge transfer on these non-radiative relaxation pathways. Our simulations included pyrrole solvated in 494 explicit water molecules equilibrated at 300 K and also employed a polarizable continuum model (PCM) to make the system more realistic and gain additional insights. In hydrated environments, the hydrogen bonding network between pyrrole and surrounding water molecules facilitates enhanced non-radiative relaxation pathways following inner valence ionization. Since these are hydrogen bonding systems, we have explored the possibility of proton transfer, which could occur in conjunction with other electronic decay processes.

Silicon-based materials has been focused as potential candidates for lithium-ion battery anodes due to their sufficient reserves and extremely high specific capacity. However, the drastic volume expansion during the cycling leads to material pulverization and instability of the solid-electrolyte interface resulting in the rapid capacity fading, which restricts their commercial application. In this study, an original synergistic effect resulting from the phase segregation of Mn-based metal organic framework (Mn-MOF) during cycling is proposed to modify silicon via a facile self-assembly method and investigated as an anode material in LIBs. The unique composite structure can effectively improve the reversibility of silicon and enhance the lithium-ion storage capability. After 400 cycles, the Si@Mn-MOF composite exhibits a good electrochemical performance, achieving a high reversible capacity retention of 1234.4 mAh g^-1 at a current density of 200 mA g^-1.

It was reported that adsorbed methyl radicals produce ethane with Ag⁰- and Au⁰-nanoparticles in aqueous media, whereas on Cu⁰-powders, the product is methanol. The source of these differences was explored computationally, using the DFT method. The results indicate that up to six radicals can be adsorbed on Ag(111) and Au(111), (top site), while only four can be adsorbed on Cu(111) (fcc site), each surface containing eight atoms. The diffusion of the radicals on the surface is very easy on silver and copper, as this is achieved with a very low barrier (0.06 eV and 0.15 eV for Ag(111) and Cu(111), respectively), while on Au(111), the barrier is higher, 0.51 eV. The formation of ethane via a reaction of two adsorbed radicals is thermodynamically plausible for all studied coverage ratios on the three surfaces, but kinetically, it is plausible at room temperature only on Au(111) and Ag(111) at full coverage. Ethane can also be produced on Au(111) and Ag(111) by a collision of a solvated radical and an adsorbed radical. This is a barrierless process. On Cu(111), the yield of such a process is CH₄(aq), and an adsorbed CH₂ which reacts further with a non-adsorbed water molecule to produce adsorbed CH₃OH.

Sodium-ion batteries (SIBs) are expected to be the next-generation large-scale energy storage technology. Organic anode materials are potential for efficient SIBs because they are not sensitive to the size of metal ions. Yet they still suffer from shortcomings such as low electrical conductivity, and solubility in electrolyte. Formation of nanocomposite with carbon materials is an efficient way to address these issues. Herein, we design a thiophene-based carboxylate compound STT, and the STT@rGO nanocomposite is also in situ formed as anode material for SIBs. The reduced graphene oxide (rGO) could improve conductivity and decrease the solubility of the anode material. Compared to the pristine STT electrode, STT@rGO delivers a reversible specific capacity of 178 mAh g^-1, with a capacity retention rate of 86 % after 1000 cycles. Moreover, full batteries are successfully assembled using the nanocomposite anode and the commercial cathode Na₃V₂(PO₄)₃, manifesting the potential applications of the nanocomposite as organic electrode materials.

This study employs first-principles methods to investigate the ORR catalytic activity of As-doped and AsN co-doped graphene. As atoms, as catalytic active sites, exhibit excellent catalytic activity. Due to the strong interaction between As and N, the stability of the As-N co-doped substrate is enhanced. In particular, As-N4 co-doped graphene not only demonstrates the best thermodynamic and kinetic stability, but also has an ORR overpotential of only 0.53 V. We also propose a method to predict the Gibbs free energy change of the system by calculating the adsorption energies of the adsorbates. This approach can streamline the process by eliminating the need to calculate the Gibbs free energy of the ORR system, making it highly advantageous for future studies on the ORR catalytic activity of multi-impurity co-doped graphene.

The centrosymmetric constraint of Friedel's law in standard x-ray diffraction limits its ability to reveal complex molecular symmetry. In contrast, twisted x-ray diffraction with vortex beams, which carry orbital angular momentum, breaks Friedel's law yielding diffraction patterns that reflect the intrinsic symmetry of molecules. Through analytical derivations and numerical simulations, we demonstrate the enhanced sensitivity of twisted x-ray diffraction to the symmetry of M-fold symmetric molecules. Our results show that, while traditional standard x-ray diffraction struggles to distinguish between structurally similar molecules with different symmetries, twisted x-ray diffraction patterns can clearly differentiate these molecules. Additionally, we show that increasing the orbital angular momentum enhances the diffraction resolution and reveals finer symmetry-specific features of the molecules. This positions twisted x-ray diffraction as a promising tool for molecular imaging, capable of revealing intricate structures with complex symmetry.