Highlights

Though researchers have been looking for solid-state electrolytes that could enhance both the safety and performance of lithium-ion batteries for decades, no thoroughly suitable candidate has yet been found. Computational screening may offer better chances of success than previous methods of investigation, largely led by chemical intuition and experiment, but such methods must also meet certain criteria. In a recent paper published in the journal Energy & Environmental Science, NCCR MARVEL researchers Leonid Kahle, Aris Marcolongo and Nicola Marzari present a suitable computational framework for predicting the diffusion of Li-ions in solid-state materials, show how to employ it in large-scale computational screening and use it to identify new ceramic compounds for further experimental investigation. 

Researchers led by Stefan Goedecker at the University of Basel have developed an algorithm allowing for the rapid identification of entire reaction pathways in complex systems. Applying it to C60 and C20H20, they show that the reaction pathways found contain valuable information on how these molecules can be synthesized. The paper was recently published in Physical Review Letters. 

Chemical engineers led by Berend Smit, MARVEL deputy director and head of the Laboratory of Molecular Simulation at EPFL have designed a material that can capture carbon dioxide from wet flue gases better than some commercial materials. The work has been published in Nature.

In a recently published paper, Relative Abundance of Z2 Topological Order in Exfoliable Two-Dimensional Insulators, researchers from MARVEL director Nicola Marzari’s Laboratory of theory and simulation of materials (THEOS) screened a comprehensive database and identified 13 monolayers that are dynamically stable and potentially exfoliable quantum spin Hall insulators. This highlights a relative abundance of such topological order of around 1%. The paper was published in Nano Letters.

NCCR MARVEL and CCMX, the Competence Centre for Materials Science and Technology, hosted their third annual Materials Science Day on October 8 to present both experimental and modeling approaches to the development of innovative new materials. The event, meant to highlight cutting-edge research and give people a chance to network, drew more than 60 people from industry and academia.

Research should be driven by societal issues—we need to pursue what is urgent and needed for the community at large. Just as the NCCR MARVEL seeks the guidance and expertise of a scientific advisory board in developing lines of research, we also seek insight from industry. 

Clémence Corminboeuf, Michele Ceriotti and colleagues at EPFL have developed a machine learning model that can predict the electron density from atomic coordinates. The approach may facilitate the characterization of non-covalent interactions, helping researchers  understand complex interactions between biomolecules and potentially assist in the design of self-assembled materials and drugs. The research was recently published in the journal Chemical Science.

A paper published in the journal Science by NCCR MARVEL's QuanSheng Wu, postdoc in the group of Oleg Yazyev at EPFL, Alexey Soluyanov, professor at the Physics Institute of the University of Zurich as well as group leader in Design & Discovery Project 6, and colleague Tomáš Bzdušek at Stanford University  introduces non-Abelian topological charges that characterize line nodes inside the momentum space of certain symmetric crystalline metals with weak spin-orbit coupling. The analysis goes beyond the standard approach to band topology, and implies the existence of 1D topological phases not present in existing classifications.

The hydrated electron has been widely studied, but the atomistic mechanism leading to its formation and the nature of the precursor states remain poorly understood. One of those states, the wet electron, has been used to explain certain spectroscopic observations, but its binding energy and atomic structure have been difficult to characterize. Now, using hybrid functional molecular dynamics simulations, NCCR MARVEL researchers have unveiled the ultrafast solvation mechanism that leads to the hydrated electron. The picture gives an unprecedented view of the nature of the wet electron, instrumental to understanding the properties of this fundamental species in liquid water. The research has been published in Chemical Science.

The modern microelectronics industry has a huge need for highly efficient electric insulators. Structures built around the medium with the lowest possible dielectric constant, that is, a vacuum, or air, may be their best bet. Metal-organic frameworks (MOFs) feature, among other advantages, large pores and poorly correlated scaffolding and so may serve this purpose well. Despite the huge potential, few studies have pursued either systematic experimental measurements or simulations to estimate the dielectric constant of MOFs. This lack of data makes it difficult to link properties and performance and hinders the design of an optimal structure–property correlation. NCCR MARVEL researchers looked to fill this gap in knowledge with a study into how the atomic and electronic structures of MOFs affect their dieletric properties. The results of their work were recently published in the Journal of the American Chemical Society. 

MARVEL researchers have developed a novel microscopic theory that is able to describe heat transport in very general ways, and applies equally well to ordered or disordered materials such as crystals or glasses and to anything in between. This is not only a significant first—no transport equation has been able so far to account simultaneously for these two regimes—it also shows, surprisingly, that heat can tunnel, quantum-mechanically, rather than diffuse away, like an atomic vibration. The new equation will also allow the accurate prediction of the performance of thermoelectric materials for the first time. With ultralow, glass-like, thermal conductivity, such materials are one of the holy grails of energy research: they can turn heat into electricity or use electricity for cooling without needing to resort to pumps and environmentally harmful gases. The article was published in Nature Physics.

NCCR MARVEL researchers have investigated strain as a means of engineering the valley structure of 2D materials. They found that it leads to remarkable improvements in conductivity—in the example of arsenene, they showed the enhancement factor to be on the order of 600%—by suppressing intervalley scattering and thus enhancing electron mobility. The approach could be used to design or discover 2D materials that combine both good carrier mobility and the energy gap needed for use in logical devices. The research has been published in Nano Letters.