Sub-diffusion and population dynamics of water confined in soft environments

We have studied by Molecular Dynamics computer simulations the dynamics of water confined in ionic surfactants phases, ranging from well ordered lamellar structures to micelles at low and high water loading, respectively. We have analysed in depth the main dynamical features in terms of mean squared displacements and intermediate scattering functions, and found clear evidences of sub-diffusive behaviour. We have identified water molecules lying at the charged interface with the hydrophobic confining matrix as the main responsible for this unusual feature, and provided a comprehensive picture for dynamics based on a very precise analysis of life times at the interface. We conclude by providing, for the first time to our knowledge, a unique framework for rationalising the existence of important dynamical heterogeneities in fluids absorbed in soft confining environments

Water confined in self-assembled ionic surfactants nano-structures

We present a coarse-grained model for ionic surfactants in explicit aqueous solutions, and study by computer simulation both the impact of water content on the morphology of the system, and the consequent effect of the formed interfaces on the structural features of the adsorbed fluid. On increasing the hydration level at ambient conditions, the model exhibits a series of three distinct phases: lamellar, cylindrical and micellar. We characterize the different structures in terms of diffraction patterns and neutron scattering static structure factors. We demonstrate that the rate of variation of the nano-metric sizes of the self-assembled water domains shows peculiar changes in the different phases. We also analyse in depth the structure of the water/confining matrix interfaces, the implications of their tunable degree of curvature, and the properties of water molecules in the different restricted environments. Finally, we discuss our results compared to experimental data and their impact on a wide range of important scientific and technological domains, where the behavior of water at the interface with soft materials is crucial

Disentangling water, ion and polymer dynamics in an anion exchange membrane

Semipermeable polymeric anion exchange membranes are essential for separation, filtration and energy conversion technologies including reverse electrodialysis systems that produce energy from salinity gradients, fuel cells to generate electrical power from the electrochemical reaction between hydrogen and oxygen, and water electrolyser systems that provide H2 fuel. Anion exchange membrane fuel cells and anion exchange membrane water electrolysers rely on the membrane to transport OH− ions between the cathode and anode in a process that involves cooperative interactions with H2O molecules and polymer dynamics. Understanding and controlling the interactions between the relaxation and diffusional processes pose a main scientific and critical membrane design challenge. Here quasi-elastic neutron scattering is applied over a wide range of timescales (100–103 ps) to disentangle the water, polymer relaxation and OH− diffusional dynamics in commercially available anion exchange membranes (Fumatech FAD-55) designed for selective anion transport across different technology platforms, using the concept of serial decoupling of relaxation and diffusional processes to analyse the data. Preliminary data are also reported for a laboratory-prepared anion exchange membrane especially designed for fuel cell applications

Data Management Plans: the Importance of Data Management in the BIG‐MAP Project[]**

Open access to research data is increasingly important for accelerating research. Grant authorities therefore request detailed plans for how data is managed in the projects they finance. We have recently developed such a plan for the EU−H2020 BIG-MAP project—a cross-disciplinary project targeting disruptive battery-material discoveries. Essential for reaching the goal is extensive sharing of research data across scales, disciplines and stakeholders, not limited to BIG-MAP and the European BATTERY 2030+ initiative but within the entire battery community. The key challenges faced in developing the data management plan for such a large and complex project were to generate an overview of the enormous amount of data that will be produced, to build an understanding of the data flow within the project and to agree on a roadmap for making all data FAIR (findable, accessible, interoperable, reusable). This paper describes the process we followed and how we structured the plan

Evidence for Atomic Hopping of Fe in Perfectly Icosahedral AlfeCu Quasicrystals by 57^{\bf 57}Fe Mössbauer Spectroscopy

By $^{57}$Fe Mössbauer spectroscopy in a special experimental set-up we have shown the existence of Fe atomic jumps in Al$_{62}$Fe$_{25.5}$Cu$_{12.5}$ perfect icosahedral quasicrystals. The (preliminary) results indicate that at 790 $^{\circ}$C 20% of the Fe atoms are jumping at a time scale corresponding to 4 $\mu{\rm e}$V

Investigating Li-ion batteries negative electrode swelling processes using electrochemical dilatometer

International audienceLi-ion batteries despite being the most commercialised electrochemical energy storage system are still suffering some drawbacks during their cycling. Indeed, several processes are taking place during cycling, i) the electrodes are “breathing” during oxidation and reduction, ii) the electrolyte is reduced and oxidised generating several surface reactions among them the well-known solid electrolyte interphase (SEI)

Investigating Li-ion batteries negative electrode swelling processes using electrochemical dilatometer

International audienc

Investigating Li-ion batteries negative electrode swelling processes using electrochemical dilatometer

International audienceLi-ion batteries despite being the most commercialised electrochemical energy storage system are still suffering some drawbacks during their cycling. Indeed, several processes are taking place during cycling, i) the electrodes are “breathing” during oxidation and reduction, ii) the electrolyte is reduced and oxidised generating several surface reactions among them the well-known solid electrolyte interphase (SEI). As an example, at the negative electrode, graphite is suffering a volume expansion of up to 10% that is generally reversible but upon long-term cycling can be a caused of fading (ref.1). This induced mechanical stress and its consequence on the electrochemical performance need to be investigated

Investigating Li-ion batteries negative electrode swelling processes using electrochemical dilatometer

International audienc