J. Appl. Cryst.の発刊に際して

Research Development on Sodium-Ion Batteries

Energy production and storage technologies have attracted a great deal of attention for day-to-day applications. In recent decades, advances in lithium-ion battery (LIB) technology have improved living conditions around the globe. LIBs are used in most mobile electronic devices as well as in zero-emission electronic vehicles. However, there are increasing concerns regarding load leveling of renewable energy sources and the smart grid as well as the sustainability of lithium sources due to their limited availability and consequent expected price increase. Therefore, whether LIBs alone can satisfy the rising demand for small- and/or mid-to-large-format energy storage applications remains unclear. To mitigate these issues, recent research has focused on alternative energy storage systems. Sodium-ion batteries (SIBs) are considered as the best candidate power sources because sodium is widely available and exhibits similar chemistry to that of LIBs; therefore, SIBs are promising next-generation alternatives. Recently, sodiated layer transition metal oxides, phosphates and organic compounds have been introduced as cathode materials for SIBs. Simultaneously, recent developments have been facilitated by the use of select carbonaceous materials, transition metal oxides (or sulfides), and intermetallic and organic compounds as anodes for SIBs. Apart from electrode materials, suitable electrolytes, additives, and binders are equally important for the development of practical SIBs. Despite developments in electrode materials and other components, there remain several challenges, including cell design and electrode balancing, in the application of sodium ion cells. In this article, we summarize and discuss current research on materials and propose future directions for SIBs. This will provide important insights into scientific and practical issues in the development of SIBs.

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Sodium-ion batteries: present and future

Room-temperature stationary sodium-ion batteries have attracted great attention particularly in large-scale electric energy storage applications for renewable energy and smart grid because of the huge abundant sodium resources and low cost. In this article, a variety of electrode materials including cathodes and anodes as well as electrolytes for room-temperature stationary sodium-ion batteries are briefly reviewed. We compare the difference in storage behavior between Na and Li in their analogous electrodes and summarize the sodium storage mechanisms in the available electrode materials. This review also includes some new results from our group and our thoughts on developing new materials. Some perspectives and directions on designing better materials for practical applications are pointed out based on knowledge from the literature and our experience. Through this extensive literature review, the search for suitable electrode and electrolyte materials for stationary sodium-ion batteries is still challenging. However, after intensive research efforts, we believe that low-cost, long-life and room-temperature sodium-ion batteries would be promising for applications in large-scale energy storage system in the near future.

Room-temperature stationary sodium-ion batteries for large-scale electric energy storage

基礎講座 電気泳動(Electrophoresis)

Effect of ion-binding and chemical phospholipid structure on the nanomechanics of lipid bilayers studied by force spectroscopy.

https://www.cell.com/biophysj/pdf/S0006-3495(05)73067-8.pdf

Effect of Temperature on the Nanomechanics of Lipid Bilayers Studied by Force Spectroscopy

https://garcia-manyeslab.org/wp-content/uploads/2013/09/BBA-2010-Garcia-Manyes.pdf

Nanomechanics of lipid bilayers by force spectroscopy with AFM: A perspective

Cholesterol (Chol) plays the essential function of regulating the physical properties of the cell membrane by controlling the lipid organization and phase behavior and, thus, managing the membrane fluidity and its mechanical strength. Here, we explore the model system DPPC:Chol by means of temperature-controlled atomic force microscopy (AFM) imaging and AFM-based force spectroscopy (AFM-FS) to assess the influence of Chol on the membrane ordering and stability. We analyze the system in a representative range of compositions up to 50 mol % Chol studying the phase evolution upon temperature increase (from room temperature to temperatures high above the T(m) of the DPPC bilayer) and the corresponding (nano)mechanical stability. By this means, we correlate the mechanical behavior and composition with the lateral order of each phase present in the bilayers. We prove that low Chol contents lead to a phase-segregated system, whereas high contents of Chol can give a homogeneous bilayer. In both cases, Chol enhances the mechanical stability of the membrane, and an extraordinarily stable system is observed for equimolar fractions (50 mol % Chol). In addition, even when no thermal transition is detected by the traditional bulk analysis techniques for liposomes with high Chol content (40 and 50 mol %), we demonstrate that temperature-controlled AFM-FS is capable of identifying a thermal transition for the supported lipid bilayers. Finally, our results validate the AFM-FS technique as an ideal platform to differentiate phase coexistence and transitions in lipid bilayers and bridge the gap between the results obtained by traditional methods for bulk analysis, the theoretical predictions, and the behavior of these systems at the nanoscale.

Influence of cholesterol on the phase transition of lipid bilayers: a temperature-controlled force spectroscopy study.

One of the hallmarks of Alzheimer's disease is the self-aggregation of the amyloid beta peptide (Abeta) in extracellular amyloid fibrils. Among the different forms of Abeta, the 42-residue fragment (Abeta1-42) readily self-associates and forms nucleation centers from where fibrils can quickly grow. The strong tendency of Abeta1-42 to aggregate is one of the reasons for the scarcity of data on its fibril formation process. We have used atomic force microscopy (AFM) to visualize in liquid environment the fibrillogenesis of synthetic Abeta1-42 on hydrophilic and hydrophobic surfaces. The results presented provide nanometric resolution of the main structures characteristic of the several steps from monomeric Abeta1-42 to mature fibrils in vitro. Oligomeric globular aggregates of Abeta1-42 precede the appearance of protofibrils, the first fibrillar species, although we have not obtained direct evidence of oligomer-protofibril interconversion. The protofibril dimensions deduced from our AFM images are consistent with a model that postulates the stacking of the peptide in a hairpin conformation perpendicular to the long axis of the protofibril, forming single beta-sheets ribbon-shaped. The most abundant form of Abeta1-42 fibril exhibits a nodular structure with a ~100-nm periodicity. This length is very similar 1) to the length of protofibril bundles that are the dominant feature at earlier stages in the aggregation process, 2) to the period of helical structures that have been observed in the core of fibrils, and 3) to the distance between regularly spaced, structurally weak fibril points. Taken together, these data are consistent with the existence of a ~100-nm long basic protofibril unit that is a key fibril building block.

Fausto Sanz

Papers

Effect of ion-binding and chemical phospholipid structure on the nanomechanics of lipid bilayers studied by force spectroscopy.

Effect of Temperature on the Nanomechanics of Lipid Bilayers Studied by Force Spectroscopy

Nanomechanics of lipid bilayers by force spectroscopy with AFM: A perspective

Influence of cholesterol on the phase transition of lipid bilayers: a temperature-controlled force spectroscopy study.

Fine structure study of Aβ1-42 fibrillogenesis with atomic force microscopy