Electrochemical materials discovery and intelligence

Design and implementation of efficient and cost-effective electrochemical devices is a complex challenge. It hinges on big-data driven knowledge at the frontiers of multi-disciplinary efforts in materials discovery and design. These massive data–driven processes, however, require intensive cognitive, yet expensive systems, including human, to determine the best design decisions. A novel approach towards Artificial Intelligence (AI) and Machine Learning (ML) algorithms can overcome the complexity of selecting advanced new materials with the predictable and desired properties. Focusing on advanced electrocatalysts for CO2 conversion as a use case, we demonstrate an AI-driven “Virtual Materials Intelligence” platform (beta) for materials data management and intelligent design equipped with an advanced user interface and predictive capabilities in view of materials properties and function. The platform combines information originating from large data sets of different origins. The data storage, data analysis, and advanced analysis algorithms enable efficient and secure data flow between several different simulation and characterization activities. The cloud-based platform ultimately aims to manage all available materials databases and relevant modeling, simulation, performance, cost, and characterization data and how they can be communicated to materials fabrication and design teams

Double layer of Platinum Electrodes: Non-Monotonic Surface Charging Phenomena and Negative Double Layer Capacitance

In this study, the refined double layer model of platinum electrodes accounts for chemisorbed oxygen species, oriented interfacial water molecules and ion size effects in solution. It results in a non-monotonic surface charging relation and a peculiar capacitance vs. potential curve with a maximum and maybe negative-defined values in the potential regime of oxide-formation. &nbsp

Approaching the Self-Consistency Challenge of Electrocatalysis with Theory and Computation

This opinion piece centers around challenges involved in developing first- principles electrochemical methods. In recent years, theory and computation have become quintessential tools to navigate the parameter space that controls the activity and stability of electrocatalytic materials and electrochemical devices. Viable methods process as input details on materials structure, composition and reaction conditions. Their output includes metrics for stability and activity, phase diagrams, as well as mechanistic insights on reaction mechanisms and pathways. The core challenge, connecting input to output, is a self-consistency problem that couples the electrode potential to variables for the electronic structure of the solid electrode, solvent properties and ion distributions in the electrolyte as well as specific properties of a boundary region in between. We will discuss a theoretical framework and computational approaches that strive to accomplish this feat

The effects of water and microstructure on the performance of polymer electrolyte fuel cells

n this paper, we present a comprehensive non-isothermal, one-dimensional model of the cathode side of a Polymer Electrolyte Fuel Cell. We explicitly include the catalyst layer, gas diffusion layer and the membrane. The catalyst layer and gas diffusion layer are characterized by several measurable microstructural parameters. We model all three phases of water, with a view to capturing the effect that each has on the performance of the cell. A comparison with experiment is presented, demonstrating excellent agreement, particularly with regard to the effects of water activity in the channels and how it impacts flooding and membrane hydration. We present several results pertaining to the effects of water on the current density (or cell voltage), demonstrating the role of micro-structure, liquid water removal from the channel, water activity, membrane and gas diffusion layer thickness and channel temperature. These results provide an indication of the changes that are required to achieve optimal performance through improved water management and MEA-component design. Moreover, with its level of detail, the model we develop forms an excellent basis for a multi-dimensional model of the entire membrane electrode assembly

Surface Configuration and Wettability of Nickel (Oxy)Hydroxides: A First-Principles Investigation

This article explores the wetting behavior of b-type nickel hydroxide, b-Ni(OH)2, and nickel oxyhydroxide, b-NiOOH, by means of first-principles calculations. Water is found to interact weakly with b-Ni(OH)2(001), but strongly with b-NiOOH(001). As unveiled with the use of ab initio molecular dynamics simulations, surface water layers at b-NiOOH(001) show a high degree of ordering correlated with a large surface polarization effect. In comparison, interfacial water at b-Ni(OH)2(001) exhibits enhanced disorder and higher mobility. The weak interaction of water with b-Ni(OH)2(001) is consistent with the small dipole moment of this surface. On the surface of b-NiOOH(001), in addition to the significantly increased surface dipole moment, unsaturated O atoms increase the number of hydrogen bonds between water molecules and the surface, resulting in strong water binding. The wettability trends found in this simulation study are consistent with experimental observations. Another theoretical observation is the increased work function of b-NiOOH(001) relative to b-Ni(OH)2(001) that agrees with experimental results reported in the literature

Unifying Theoretical Framework for Deciphering the Oxygen Reduction Reaction on Platinum

Rapid conversion of oxygen into water is crucial to the operation of polymer electrolyte fuel cells and other emerging electrochemical energy technologies. Chemisorbed oxygen species play double-edged roles in this reaction, acting as vital intermediates on one hand and site-blockers on the other. Any attempt to decipher the oxygen reduction reaction (ORR) must first relate the formation of oxygen intermediates to basic electronic and electrostatic properties of the catalytic surface, and then link it to parameters of catalyst activity. An approach that accomplishes this feat will be of great utility for catalyst materials development and predictive model formulation of electrode operation. Here, we present a theoretical framework for the multiple interrelated surface phenomena and processes involved, particularly, by incorporating the double-layer effects. It sheds light on the roles of oxygen intermediates and gives out the Tafel slope and exchange current density as continuous functions of electrode potential. Moreover, it develops the concept of a rate determining term which should replace the concept of a rate determining step for multi-electron reactions, and offers a new perspective on the volcano relation of the ORR. &nbsp

Collaboration between education and health professionals for the assessment of speech development

Im Spannungsfeld Kita, Schule und Sprachtherapie ist multifaktorielle Expertise gefragt, um sprachliche Fähigkeiten von Kindern einzuschätzen und gegebenenfalls geeignete Förder- oder Therapiemaßnahmen abzuleiten. Eine besondere Herausforderung stellt dabei die strukturelle Komplexität der Versorgung hinsichtlich der verschiedenen Akteur*innen, Organisationen und Versorgungssysteme dar. Ziel der Studie war es, in Form einer Kontextanalyse die interprofessionellen Prozesse und Strukturen bzgl. kindlicher Sprachentwicklung zu rekonstruieren sowie fördernde und hemmende Faktoren zu identifizieren. Es wurden fünf Fokusgruppen mit jeweils drei Expert*innen aus den Berufsgruppen Erzieher*in, Sprachtherapeut*in, (Grundschul-)Lehrer*in, Sonderpädagog*in und Mediziner*in durchgeführt und ausgewertet, wobei auf die Methode der qualitativen Inhaltsanalyse mittels Extraktion zurückgegriffen wurde. Aus den Analysen ergab sich, dass personelle und ökonomische Ressourcen sowie klar kommunizierte rechtliche Rahmenbedingungen auf Systemebene eine Rolle spielen. Organisationsbezogen konnte die Gestaltung der Kommunikations- und Dokumentationsprozesse als wesentlicher Faktor für das Gelingen interprofessioneller Zusammenarbeit identifiziert werden. Das Engagement der Akteur*innen und der adäquate Einbezug von Erziehungsberechtigten sind ebenfalls als Einflussfaktor zu nennen. Die Expert*innen sehen ein hohes Potential in interprofessioneller Zusammenarbeit. Eine solche Zusammenarbeit ist ihrer Ansicht nach besonders wertvoll, wenn es um die Qualität der Beurteilung des kindlichen (Sprach-)Entwicklungsstandes (1) und der Förder- und Therapieangebote (2) geht. Es besteht ein Bedarf an der Gestaltung interprofessioneller Netzwerke über eine zentrale, sichere, niedrigschwellige und digitale Dokumentations- und Austauschplattform für die fallzentrierte Zusammenarbeit. (DIPF/Orig.)Across daycare, school and speech and language therapy (SLT), multifactorial expertise is required to assess the language skills of children and, if necessary, define suitable support or therapeutical measures. The structural complexity of health care, welfare and public education involving various stakeholders, organisations and care systems poses a particular challenge. The aim of the study was a context analysis to reconstruct interprofessional processes and structures with regard to children’s language development and to identify promoting and inhibiting factors. Five focus group interviews, involving three experts each, were conducted and analysed, using the method of qualitative content analysis by means of extraction. The analyses showed that staff and economic resources as well as clearly communicated legal framework conditions play a role at the system level. In terms of organisation, the nature of communication and documentation processes was identified as an essential factor for the success of interprofessional cooperation. The commitment of stakeholders and the adequate involvement of caregivers can also be mentioned as an influencing factor. The participants see high value in interprofessional cooperation. Such cooperation, in their view, is particularly valuable when it comes to the quality of the assessment of the language development of children (1) and of the support and therapy services (2). This study thus suggests that there is a need to create and sustain interprofessional networks through a central, secure, low-threshold and digital documentation and exchange platform for case-centred cooperation. (DIPF/Orig.

The hydration state of HO−^-(aq)

The HO$^-$(aq) ion participates in myriad aqueous phase chemical processes of biological and chemical interest. A molecularly valid description of its hydration state, currently poorly understood, is a natural prerequisite to modeling chemical transformations involving HO$^-$(aq). Here it is shown that the statistical mechanical quasi-chemical theory of solutions predicts that $\mathrm{HO\cdot[H_2O]_3{}^-}$ is the dominant inner shell coordination structure for HO$^-$(aq) under standard conditions. Experimental observations and other theoretical calculations are adduced to support this conclusion. Hydration free energies of neutral combinations of simple cations with HO$^-$(aq) are evaluated and agree well with experimental values.Comment: 10 pages, 1 figur