다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

Each cell of a battery stores electrical energy as chemical energy in two electrodes, a reductant (anode) and an oxidant (cathode), separated by an electrolyte that transfers the ionic component of the chemical reaction inside the cell and forces the electronic component outside the battery. The output on discharge is an external electronic current I at a voltage V for a time Δt. The chemical reaction of a rechargeable battery must be reversible on the application of a charging I and V. Critical parameters of a rechargeable battery are safety, density of energy that can be stored at a specific power input and retrieved at a specific power output, cycle and shelf life, storage efficiency, and cost of fabrication. Conventional ambient-temperature rechargeable batteries have solid electrodes and a liquid electrolyte. The positive electrode (cathode) consists of a host framework into which the mobile (working) cation is inserted reversibly over a finite solid–solution range. The solid–solution range, which is...

The Li-ion rechargeable battery: a perspective.

Li-ion battery technology has become very important in recent years as these batteries show great promise as power sources that can lead us to the electric vehicle (EV) revolution. The development of new materials for Li-ion batteries is the focus of research in prominent groups in the field of materials science throughout the world. Li-ion batteries can be considered to be the most impressive success story of modern electrochemistry in the last two decades. They power most of today's portable devices, and seem to overcome the psychological barriers against the use of such high energy density devices on a larger scale for more demanding applications, such as EV. Since this field is advancing rapidly and attracting an increasing number of researchers, it is important to provide current and timely updates of this constantly changing technology. In this review, we describe the key aspects of Li-ion batteries: the basic science behind their operation, the most relevant components, anodes, cathodes, electrolyte solutions, as well as important future directions for R&D of advanced Li-ion batteries for demanding use, such as EV and load-leveling applications.

Challenges in the development of advanced Li-ion batteries: a review

Li-ion battery materials: present and future

Lithium transition-metal oxides used as intercalation compounds for rechargeable lithium batteries are widely studied in search of structural stability and improved electrochemical performance. Cathode materials belonging to the 4-volt class electrodes were synthesized by wet-chemistry methods, i.e., sol-gel, combustion or co-precipitation techniques. It is shown that synthesis greatly affects the electrochemistry and cycle life characteristics of the cathodes. Extensive damage including local strain variation, nanodomain formation, and changes in cation ordering, has been observed by local probes such as Raman and FTIR spectroscopy. In this work we wish to show the relationship between the local cationic environment and electrochemical characteristics of the 4-volt cathodes. Materials such as LiMn2O4, LiCoO2, LiNi1−yCoyO2, LiNi1−yCoyVO4, and LiMoVO6 are investigated.

4-Volt cathode materials for rechargeable lithium batteries wet-chemistry synthesis, structure and electrochemistry

Amongst a number of different cathode materials, the layered nickel-rich LiNiyCoxMn1−y−xO2 and the integrated lithium-rich xLi2MnO3·(1 − x)Li[NiaCobMnc]O2 (a + b + c = 1) have received considerable attention over the last decade due to their high capacities of ~195 and ~250 mAh·g−1, respectively. Both materials are believed to play a vital role in the development of future electric vehicles, which makes them highly attractive for researchers from academia and industry alike. The review at hand deals with both cathode materials and highlights recent achievements to enhance capacity stability, voltage stability, and rate capability, etc. The focus of this paper is on novel strategies and established methods such as coatings and dopings.

Study of Cathode Materials for Lithium-Ion Batteries: Recent Progress and New Challenges

The growth of vanadium oxide films with controlled surface structure for optimum-device performance often presents a significant technological problem for theoretical and experimental investigation. In the present investigation, V 2 O 5 thin films were prepared by pulsed-laser deposition (PLD) and were studied for their surface-structure evolution in relation to the growth temperature. The deposition was made onto various substrate materials and in the wide range of substrate temperatures, 30–500 °C, keeping the oxygen partial pressure at 100 mTorr. The films were characterized using atomic force microscopy (AFM) for sample surface imaging in order to understand the effect of substrate temperature and substrate material characteristics on the growth behavior. The results gave a consistent picture of the evolution of vanadium oxide film surface morphology and microstructure in terms of growth, behavior, shape, and distribution of the particles making up films. The grain size, surface texture, and external morphology of V 2 O 5 thin films were found to be highly sensitive to the substrate temperature while the effect of substrate material characteristics is dominant only at higher temperatures. The grain size varied in the range 50–600 nm and the surface roughness in the range 9–20 nm with the increasing substrate temperature for crystalline vanadium oxide thin films. The growth mechanism of pulsed-laser deposited vanadium oxide films with oriented structure has been discussed in detail.

On the growth mechanism of pulsed-laser deposited vanadium oxide thin films

The layered LiNi0.6Co0.4O2 powders were synthesized at low temperature by a sol-gel method using citric acid as a chelating agent. Submicron-sized particles of the precursor were obtained at temperature below 400°C and microcrystalline powders were grown by thermal treatment at 700°C for 4 h in air. The carboxylic-based acid acted such as a fuel, decomposed the homogeneous precipitate of metal complexes at low temperature, and yielded the free impurity LiNi0.6Co0.4O2 single-phase suitable for electrochemical application. The synthesized products have been characterized by structural (XRD, SEM), spectroscopic (FTIR, Raman) and thermal (DTA/TG) analyses. Raman and FTIR measurements provide information on the local environment of the cationic sublattice of LiNi0.6Co0.4O2 solid solution. Electrochemical performance of the synthesized products in rechargeable Li cells were evaluated by employing as cathodes in non-aqueous organic electrolyte mixture of 1M LiPF6 in EC + DMC. The electrochemical behaviour of synthesized LiNi0.6Co0.4O2 is discussed in relation with its synthesis procedure.

Studies of LiNi0.6Co0.4O2 Cathode Material Prepared by the Citric Acid-Assisted Sol-Gel Method for Lithium Batteries

The natural inhabitants of the gastrointestinal tract play a key role in the maintenance of human health. Over the last century, the changes on the behavior of our modern society have impacted the diversity of this gut microbiome. Among the strategies to restore gut microbial homeostasis, the use of probiotics has received a lot of attention. Probiotics are living microorganisms that promote the host health when administered in adequate amounts. Its popularity increase in the marketplace in the last decade draws the interest of scientists in finding suitable methods capable of delivering adequate amounts of viable cells into the gastrointestinal tract. Encapsulation comes into the scene as an approach to enhance the cells survival during processing, storage and consumption. This paper provides a comprehensive perspective of the probiotic field at present time focusing on the academia and industry scenarios in the past few years in terms of encapsulation technologies employed and research insights including patents. The analysis of the encapsulation technologies considering food processing costs and payload of viable bacteria reaching the gastrointestinal tract would result into successful market novelties. There is yet a necessity to bridge the gap between academia and industry.

https://hal.univ-lorraine.fr/hal-01496637/document

Christian M. Julien

Papers

4-Volt cathode materials for rechargeable lithium batteries wet-chemistry synthesis, structure and electrochemistry

Study of Cathode Materials for Lithium-Ion Batteries: Recent Progress and New Challenges

On the growth mechanism of pulsed-laser deposited vanadium oxide thin films

Studies of LiNi0.6Co0.4O2 Cathode Material Prepared by the Citric Acid-Assisted Sol-Gel Method for Lithium Batteries

Smart materials for energy storage in Li-ion batteries