Li adsorption and diffusion on the surfaces of molybdenum dichalcogenides MoX2 (X = S, Se, Te) monolayers for lithium-ion batteries application: a DFT study.

CONTEXT: We study some of the most high performance electrode materials for lithium-ion batteries. These comprise molybdenum dichalcogenide MoX2 (molybdenum disulfide MoS2, molybdenum diselenide MoSe2, molybdenum ditelluride MoTe2). The stability is studied by calculating cohesive energy and formation energy. Structural, electronic, and electrical properties are well defined, and these structures show a direct gap. Lithium adsorption at different sites, theoretical storage capacity, and lithium diffusion path are determined. Our study findings suggest that the adsorption of Li on the preferred site on the surface of the MoX2 monolayer maintains its semiconductor behavior. Comparing the activation energy barrier of these structures with other monolayers such as graphene or silicene, we found that MoX2 shows low lithium diffusion energy and good storage capacity, which indicates that the MoX2 is well suited as an anode material for lithium-ion batteries. Our research can offer new ideas for experimental and theoretical design and new anode materials for lithium-ion batteries (LIB). METHODS: The studies were performed with Quantum ESPRESSO package based on density functional theory (DFT), plane waves, and pseudopotentials (PWSCF) to calculate the physical properties of MoX2 (X = S, Se, Te), lithium adsorption, and diffusion on their surfaces and the storage capacity of these structures. The BoltzTraP code is used to calculate thermoelectric properties.

Kinetic control concept for the diffusion processes of paracetamol active molecules across affinity polymer membranes from acidic solutions.

BACKGROUND: Paracetamol compound remains the most used pharmaceutical as an analgesic and antipyretic for pain and fever, often identified in aquatic environments. The elimination of this compound from wastewater is one of the critical operations carried out by advanced industries. Our work objective was to assess studies based on membrane processes by using two membranes, polymer inclusion membrane and grafted polymer membrane containing gluconic acid as an extractive agent for extracting and recovering paracetamol compound from aqueous solutions. RESULT: The elaborated membrane characterizations were assessed using Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Kinetic and thermodynamic models have been applied to determine the values of macroscopic (P and J0), microscopic (D* and Kass), activation and thermodynamic parameters (Ea, ΔH#, ΔS#, ΔH#diss, and ΔH#th). All results showed that the PVA-GA was more performant than its counterpart GPM-GA, with apparent diffusion coefficient values (107 D*) of 41.807 and 31.211 cm2 s-1 respectively, at T = 308 K. In addition, the extraction process for these membranes was more efficient at pH = 1. The relatively low values of activation energy (Ea), activation association enthalpy (ΔH≠ass), and activation dissociation enthalpy (ΔH≠diss) have indicated a kinetic control for the oriented processes studied across the adopted membranes much more than the energetic counterpart. CONCLUSION: The results presented for the quantification of oriented membrane process ensured clean, sustainable, and environmentally friendly methods for the extraction and recovery of paracetamol molecule as a high-value substance.