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Grigoryeva O.,Ukrainian Academy of Sciences | Fainleib A.,Ukrainian Academy of Sciences | Gusakova K.,Ukrainian Academy of Sciences | Starostenko O.,Ukrainian Academy of Sciences | And 5 more authors.
Macromolecular Symposia | Year: 2014

Nanoporous thermostable polycyanurate (PCN) films were generated by in-situ metal complex-catalyzed polycyclotrimerization of 4,4′-ethylidenediphenyl dicyanate in the presence of 20-50 wt.% of inert high-boiling temperature liquids as porogens, i.e. dioctyl, dibutyl or dimethyl phthalates (DOP, DBP or DMP), followed by their extraction from the densely crosslinked PCN frameworks, drying, and additional annealing at various temperatures. The nanoporous structure for all PCN-based films developed was investigated by SEM, BET, and DSC-based thermoporometry. Furthermore, the thermal and dielectric properties of the nanoporous films were also examined. The method developed allows producing nanoporous films for membranes with controlled thermal and dielectric properties as well as porosity parameters. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Abstract: This technology is significant as it allows the thermally durable Li-ion battery to be used in a wider variety of applications, such as large-scale industrial machines with motors, and medical machines which need to be heated for autoclave sterilization. Since this technology does not require the cooling system common in conventional Li-ion batteries, it is expected to lead to further developments of compact battery systems and reduce overall costs. The high energy density Li-ion battery is already being used as power sources in applications such as portable devices (smartphones and tablets), electric vehicles and adjustor of the supply and demand of renewable energy. The conventional Li-ion battery consists of a separator, a positive electrode layer and a negative electrode layer (Fig.1 (a)). The battery is filled with organic electrolyte solution in which lithium ion conducts between the two electrode layers during the charge and discharge process. An issue of the conventional Li-ion battery, with the organic electrolyte solution, is thermal durability. The upper operating temperature is limited to around 60°C owing to volatility of the organic electrolyte solution. Consequently, it is difficult to use the conventional Li-ion battery in a high temperature environment without a cooling system. Therefore, the solid electrolyte with no volatility has been developed for the utilization of Li-ion battery in a high temperature environment. The lithium ion conductivity of solid electrolyte, however, is lower than that of the organic electrolyte solution, and the internal resistance of all-solid-state Li-ion battery should be reduced for its commercialization. Prof. Shin-ichi Orimo's lab in AIMR and the Institute for Material Research at Tohoku University have been conducting research on LiBH4-based complex hydrides as novel and solid electrolytes. They have confirmed the fast lithium ion conductivity in the wide temperature range from room temperature to 150°C. ### Details of the technology developed are as below: Composite positive electrode layer to suppress the decomposition of active materials at interface*1 Adhesive layer for reducing the interface resistance between solid electrolyte and composite positive electrode layer *1 Interface: Boundary formed between different solid materials This research was part of a collaborative project between Hitachi and AIMR called "Collaborative Research for Next Generation Innovative Battery." The findings of this research were partially presented on November 13, 2015 at the 56th Battery Symposium, held in Aichi Prefecture. For more information, please click If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.


Chen Y.,Tohoku University | Li Y.,Institute for Material Research | Kurosu S.,Institute for Material Research | Yamanaka K.,Institute for Material Research | And 2 more authors.
Wear | Year: 2014

Cobalt-chromium-molybdenum (CoCrMo) alloys are widely applied as wear-resistant material. This article aims to illustrate the influence of phase constitution and precipitate morphology on the wear behavior of hot-pressed high carbon alloys. Wear behavior of two kinds of CoCrMo alloys, HP (hot-pressed) and HPA (hot-pressed+annealing) with various microstructure, hardness and surface topography were evaluated in detail. The ε phase dominant HP alloy with homogenous lamellar precipitates demonstrates higher hardness, consequently lower coefficient of friction and prominent wear resistance with mild sliding wear. In contrary, the γ phase dominant HPA alloy with carbide-free grains was characterized by abrasive wear of micro grooves. The matrix hardness strengthened by ε phase is more significant to affect wear behavior than precipitate hardening. Homogenous lamellar precipitates have a stand-out effect to block abrasion and accumulate tribochemical products. © 2014. Source


Depan D.,Institute for Material Research | Pratheep Kumar A.,University of Queensland | Singh R.P.,University of Pune | Misra R.D.K.,Institute for Material Research
Materials Science and Technology (United Kingdom) | Year: 2014

Enzymatic degradation of nanohybrid based on intercalation of chitosan (CS) within the galleries of montmorillonite (MMT) clay and grafted with poly(lactic acid) (PLA) was studied using esterase enzyme in phosphate buffered solution. Chitosan was first intercalated between the galleries of natural unmodified sodium MMT clay and subsequently grafted with PLA to prepare nanohybrids of CS-g-PLA/MMT. The prepared membranes were characterised by X-ray diffraction, transmission electron microscopy and NMR spectroscopy. The specimens were then subjected to enzymatic degradation to understand the effect of copolymerisation with PLA and the effect of incorporation of MMT in the CS matrix. The presence of MMT clay provided stability towards degradation of polymer matrix because of nanoscale dispersibility, thereby acting as a barrier towards the permeation of water molecules to induce hydrolysis of PLA. Similarly, the grafting of CS with crystalline PLA stabilised the CS matrix towards degradation, rendering it suitable for tissue engineering applications. © 2014 Institute of Materials, Minerals and Mining. Source


« Largest ultra-fast EV charging station goes live in Beijing; supporting electric buses out of Xiaoying Terminal | Main | USDOT launches Smart City Challenge; up to $40M award from DOT, $10M from Vulcan » Hitachi, Ltd. and Tohoku University’s Advanced Institute for Material Research (AIMR) have demonstrated technology reducing the internal resistance of all-solid-state lithium ion batteries (Li-ion battery) through the use of LiBH -based complex hydrides as novel solid electrolytes. The reduction of internal resistance improves the charge-discharge performance of the all-solid-state Li-ion battery, resulting in the batteries (capacity: 2 mAh, density: 30 Wh/L) successfully operating at temperatures as high as 150 ˚C with a discharge capacity of 90% of theoretical value. This technology is significant as it allows the thermally durable Li-ion battery to be used in a wider variety of applications. Because this technology does not require the cooling system common in conventional Li-ion batteries, Hitachi expects it to lead to the development of more compact battery systems and to reduce overall costs. This research was part of a collaborative project between Hitachi and AIMR has developed the new technology to reduce the internal resistance that is a factor of deterioration of charge-discharge performance. A conventional Li-ion battery consists of a separator, a positive electrode (cathode), and a negative electrode (anode). The battery is filled with organic electrolyte solution in which lithium ions move between the two electrode layers during the charge and discharge process. One issue with conventional Li-ion batteries is the thermal durability of the organic electrolyte solution. The upper operating temperature is limited to around 60 ˚C owing to the volatility of the organic electrolyte. Consequently, it is difficult to use the conventional Li-ion battery in a high temperature environment without a cooling system. While solid electrolytes with no volatility have been developed for use in a high temperature environment, the lithium ion conductivity of the solid electrolyte, is lower than that of the organic electrolyte solution. The internal resistance of all-solid-state Li-ion battery needs to be reduced for its commercialization. Details of the new battery technology include: Composite positive electrode layer to suppress the decomposition of active materials at interface. One potential issue is that Li-ion conductivity will be inhibited by the decomposition of the cathode material, which is reduced by LiBH -based complex hydrides. To solve this issue, a Li-B-Ti-O-based oxide material was developed to form a dense composite positive electrode with the active materials. The Li-B-Ti-O in the electrode effectively protected the active materials, and suppressed the increment of internal resistance caused by the decomposition. In consequence, the discharge capacity of the battery was improved from 0 to 50% of theoretical value. Adhesive layer for reducing the interface resistance between solid electrolyte and composite positive electrode layer.Another issue is that the composite cathode material and the metal hydride complex solid electrolyte layer were delaminated due to the volume change of the active materials during charge-discharge reaction. This causes incremental interfacial resistance by poor lithium ion conduction at the delaminated interface. To prevent delamination of the interface, the team developed an amide-added metal hydride complex with a low melting point for use as an adhesive layer. As a result, the internal resistance of the all-solid-state Li-ion battery was successfully reduced to 1/100 of the value compared to that of a battery with no adhesive layer. The discharge capacity was improved up to 90% at 150 ˚C by applying the two technologies. In addition, the degradation of the discharge capacity during charge-discharge cycles was effectively suppressed and the stable charge-discharge of the all-solid-state Li-ion battery was confirmed. The researchers said that now that they have verified the fundamental operation of a thermally durable all-solid-state Li-ion battery, they intend to look into further improving battery capacity, energy density and charge-discharge duration. This research was part of a project between Hitachi and AIMR called “Collaborative Research for Next Generation Innovative Battery”. The findings of this research were partially presented on 13 November at The 56th Battery Symposium in Japan.

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