Cathode Design Based on Nitrogen Redox and Linear Coordination of Cu Center for All-Solid-State Fluoride-Ion Batteries.

All-solid-state fluoride-ion batteries (FIBs) have attracted extensive attention as candidates for next-generation energy storage devices; however, promising cathodes with high energy density are still lacking. In this study, CuN is investigated as a cathode material for all-solid-state fluoride-ion batteries, which offers enough anionic vacancies around the 2-fold coordinated Cu center for F intercalation, thereby enabling a multielectron-transferred fluorination process. The contribution of both cationic and anionic redox to charge compensation, in particular, the generation of molecular nitrogen species in highly charged states, has been proved by several synchrotron-radiation-based spectroscopic technologies.

Fluoride Ion Storage and Conduction Mechanism in Fluoride Ion Battery Positive Electrode, Ruddlesden-Popper-Type Layered Perovskite LaSrMnO Crystal.

Structural characteristics on fluoride ion storage and conduction mechanism in LaSrMnO, and its fluoridated materials, LaSrMnOF and LaSrMnOF, for an all-solid-state fluoride ion battery positive electrode with a high volumetric capacity surpassing those of lithium-ion ones have been revealed using the Rietveld method and maximum entropy method. In LaSrMnO, once the F ions are taken into the NaCl slabs in its crystal through the charging process, it forms two stable fluoride compounds, LaSrMnOF and LaSrMnOF, with the help of the Mn oxidation reaction. In these oxyfluorides, thermal vibrations of the F ions inserted are much larger, especially in the - plane, than along the axis.

Double-Layered Perovskite Oxyfluoride Cathodes with High Capacity Involving O-O Bond Formation for Fluoride-Ion Batteries.

Developing electrochemical high-energy storage systems is of crucial importance toward a green and sustainable energy supply. A promising candidate is fluoride-ion batteries (FIBs), which can deliver a much higher volumetric energy density than lithium-ion batteries. However, typical metal fluoride cathodes with conversion-type reactions cause a low-rate capability.

Acidity effects of medium fluids on anhydrous proton conductivity of acid-swollen block polymer electrolyte membranes.

Proton-conductive polymer electrolyte membranes (PEMs) were prepared by infiltrating sulfuric acid (Sa) or phosphoric acid (Pa) into a polystyrene--poly(4-vinylpyridine)--polystyrene (S-P-S) triblock copolymer. When the molar ratio of acid to pyridyl groups in S-P-S, , the acid doping level (ADL), is below unity, the P-block/acid phase in the PEMs exhibited a moderately high glass transition temperature ( ) of ∼140 °C because of consumption of acids for forming the acid-base complexes between the pyridyl groups and the acids, also resulting in almost no free protons in the PEMs; therefore, the PEMs were totally glassy and exhibited almost no anhydrous conductivity. In contrast, when ADL is larger than unity, the s of the phase composed of acid and P blocks were lower than room temperature, due to the excessive molar amount of acid serving as a plasticizer.

Materials informatics approach to understand aluminum alloys.

The relations between the mechanical properties, heat treatment, and compositions of elements in aluminum alloys are extracted by a materials informatics technique. In our strategy, a machine learning model is first trained by a prepared database to predict the properties of materials. The dependence of the predicted properties on explanatory variables, that is, the type of heat treatment and element composition, is searched using a Markov chain Monte Carlo method.

Formation of strong 1-FePd/α-Fe nanocomposite magnets by visualizing efficient exchange coupling.

Conceptual nanocomposite magnets (NCMs) composed of exchange-coupled hard/soft magnetic phases have been expected to show excellent magnetic performance based on simultaneous high coercivity ( ) and high saturation magnetization ( ). In our previous works, however, the was considerably lower than its theoretical value ( ), which prevented us from improving the performance of NCMs. Here, we show that the of isolated particulate 1-FePd/α-Fe NCMs is dominated by their phase segregation into core/shell-like structures Janus-like structures.

Non-Aqueous Primary Li-Air Flow Battery and Optimization of its Cathode through Experiment and Modeling.

A primary Li-air battery has been developed with a flowing Li-ion free ionic liquid as the recyclable electrolyte, boosting power capability by promoting superoxide diffusion and enhancing discharge capacity through separately stored discharge products. Experimental and computational tools are used to analyze the cathode properties, leading to a set of parameters that improve the discharge current density of the non-aqueous Li-air flow battery. The structure and configuration of the cathode gas diffusion layers (GDLs) are systematically modified by using different levels of hot pressing and the presence or absence of a microporous layer (MPL).

Equivalence of the EMD- and NEMD-based decomposition of thermal conductivity into microscopic building blocks.

Thermal conductivity of a material can be comprehended as being composed of microscopic building blocks relevant to the energy transfer due to a specific microscopic process or structure. The building block is called the partial thermal conductivity (PTC). The concept of PTC is essential to evaluate the contributions of various molecular mechanisms to heat conduction and has been providing detailed knowledge of the contribution.

Polymer Electrolyte Fuel Cells Employing Heteropolyacids as Redox Mediators for Oxygen Reduction Reactions: Pt-Free Cathode Systems.

In this study, the heteropolyacids of H3+xPVxMO12-xO40 (x = 0, 2, and 3) were applied as redox mediators for the oxygen reduction reaction in polymer electrolyte fuel cells, of which the cathode is free from the usage of noble metals such as Pt/C. In this system, the electrochemical reduction of heteropolyacid over the carbon cathode and the subsequent reoxidation of the partially reduced heteropolyacid by exposure to the dissolved oxygen in the regenerator are important processes for continuous power generation. Thus, the redox properties of catholytes containing these heteropolyacids were investigated in detail.

Effects of molecular structure on microscopic heat transport in chain polymer liquids.

In this paper, we discuss the molecular mechanism of the heat conduction in a liquid, based on nonequilibrium molecular dynamics simulations of a systematic series of linear- and branched alkane liquids, as a continuation of our previous study on linear alkane [T. Ohara et al., J.

Dispersion of Rod-like Particles of Nafion in Salt-Free Water/1-Propanol and Water/Ethanol Solutions.

The dispersion of perfluorinated sulfonic acid ionomers in catalyst inks is an important factor controlling the performance of catalyst layers in membrane electrode assemblies of proton exchange membrane fuel cells (PEMFCs). The effect of water/alcohol composition on the dispersion of H-Nafion in water/1-propanol and water/ethanol solutions was studied by dynamic light scattering (DLS), small-angle X-ray scattering (SAXS), and (19)F nuclear magnetic resonance ((19)F NMR) spectroscopy. Hydrodynamic radii calculated from DLS decay profiles and the radii and interparticle distance of rod-like particles derived from SAXS profiles showed almost the same dependence on alcohol concentration.