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Volume 83 , Issue 10
Showing 1-36 articles out of 36 articles from the selected issue
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Innovative Battery Development
Visions
Headline
  • Hideki IBA
    Volume 83 (2015) Issue 10 Pages 797-802
    Released: October 05, 2015
    JOURNALS OPEN ACCESS
    The development of high energy density devices produces a dramatic improvement in the cruising range of electric vehicles and significantly contributes to realizing a sustainable society. In recent years, innovative batteries, such as all-solid battery, metal-air battery and sodium-ion battery, etc., which are estimated to provide a superior battery performance better than the latest lithium-ion battery, are now being given significant attention. Meanwhile, a number of breakthroughs are required in order to achieve practical use of these innovative batteries. In this paper, we summarized the current research approaches of these innovative batteries.
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Communications
Articles
  • Yasuaki MATSUDA, Masaki MATSUI, Takahiro SANDA, Yusuke TAKASHI, Nobuyu ...
    Volume 83 (2015) Issue 10 Pages 870-873
    Released: October 05, 2015
    JOURNALS OPEN ACCESS
    The crystal growth process of LiNi1/2Mn3/2O4 was investigated and the octahedral shaped LiNi1/2Mn3/2O4 was successfully synthesized by a low temperature synthesis. The morphology change was accelerated by the spinel-rocksalt phase transformation caused by the oxygen loss. After re-oxidation, high crystalline LiNi1/2Mn3/2O4 with octahedral morphology was obtained. High crystalline LiNi1/2Mn3/2O4 with the particle size of 1–3 µm was obtained by the low temperature synthesis controlling the oxygen partial pressure. High crystalline LiNi1/2Mn3/2O4 crystallized at 850°C exhibited an initial charge capacity of 145 mAh g−1 and an initial discharge capacity of 137 mAh g−1 with a plateau at 4.7 V, and 90% of cycle retention after 100 cycles at 60°C. Microparticulation of high crystalline LiNi1/2Mn3/2O4 enhanced the discharge capacity.
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  • Masaki MATSUI, Shotaro DEGUCHI, Hiroko KUWATA, Nobuyuki IMANISHI
    Volume 83 (2015) Issue 10 Pages 874-878
    Released: October 05, 2015
    JOURNALS OPEN ACCESS
    Electrolyte decomposition processes on cathode and anode active materials significantly affect to the cycle life and the calendar life of lithium-ion batteries. Here we designed a new in-operando FTIR spectroscopy cell to investigate the decomposition process of the electrolyte solutions. The cell is compatible with various cathodes and anodes for lithium-ion batteries and the charging-discharging rate can be increased up to 1 C. In the case of the conventional cathode active material LiMn2O4, the in-operando spectra shows adsorption and solvation process of the electrolyte solvent molecules, while no clear evidence of the electrolyte oxidation process is observed. On the other hand, the solid electrolyte interphase (SEI) layer formation processes on graphite anodes are clearly observed. Hence, we think the new measurement technique should be a powerful tool for the development of electrolyte additives.
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  • Yasushi IDEMOTO, Yusuke SERA, Naoya ISHIDA, Naoto KITAMURA
    Volume 83 (2015) Issue 10 Pages 879-884
    Released: October 05, 2015
    JOURNALS OPEN ACCESS
    The average and local crystal structures, and the electronic structure of 0.4Li2MnO3-0.6LiMn1/3Ni1/3Co1/3O2 were investigated using a combination of a pair distribution function (PDF) analysis and first-principles calculations. A Rietveld analysis showed that the sample had a Li2MnO3-type structure (space group: C2/m) and that Ni and Co existed at two sites, 4g and 2b, in the transition metal layer. Based on the maximum entropy method using synchrotron X-ray diffraction data, and first-principles calculations, it was determined that the covalencies between 2b and 8j sites in the transition metal layer, and between 2c and 8j sites in the lithium layer, were relatively low. In addition, based on the average length of bonds between transition metal and oxygen ions in the local structure determined by a PDF analysis using synchrotron X-ray and neutron total scattering data, and the ionic radius, the valence of Mn, Ni and Co in this material before charging was tetravalent, between divalent and trivalent, and trivalent, respectively. These results were consistent with the valence obtained from the density of states calculated by the WIEN2k code.
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  • Ayuko KITAJOU, Eiji KOBAYASHI, Shigeto OKADA
    Volume 83 (2015) Issue 10 Pages 885-888
    Released: October 05, 2015
    JOURNALS OPEN ACCESS
    Iron-based conversion cathode, FeOF is attractive, because of the low cost and the large specific capacity. However, the synthesis is not easy and it cannot be used as cathode against carbonaceous anode. To overcome these drawbacks, we focused on the LiFeOF phase, which has the same chemical composition as the discharged intermediate product of FeOF cathode. LiFeOF can be easily synthesized from LiF and FeO by the dry ball-milling method at room temperature. The reversible capacity was 292 mAh g−1 with an average voltage of 2.5 V and an energy density over 700 Wh kg−1, which is higher than that of LiFePO4. In addition, we confirmed the feasibility of LiFeOF cathode against Li4Ti5O12 anode.
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  • Takuya MATSUYAMA, Minako DEGUCHI, Akitoshi HAYASHI, Masahiro TATSUMISA ...
    Volume 83 (2015) Issue 10 Pages 889-893
    Released: October 05, 2015
    JOURNALS OPEN ACCESS
    We have successfully prepared amorphous MoS3 (a-MoS3) by ball milling a mixture of Mo metal and sulfur and investigated structural changes during the charge-discharge processes. The XPS measurements revealed that a-MoS3 should consist of Mo4+, S22−, and S2−. In the XRD profiles of the a-MoS3 electrodes after the initial discharge and charge tests, only the halo patterns due to the amorphous state were observed without crystalline diffraction peaks. The HR-TEM observations of a-MoS3 electrodes during the 1st discharge process revealed that the lattice fringes due to MoS2 layer structure disappeared gradually. However, the lattice fringes like MoS2 were also observed after the 1st charge. The HR-TEM image after the 10th charge did not show the lattice fringes of MoS2. These results of HR-TEM observations suggested that the reversible structural changes of a-MoS3 occurred.
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  • Keita FUNAYAMA, Takashi NAKAMURA, Naoaki KUWATA, Junichi KAWAMURA, Tat ...
    Volume 83 (2015) Issue 10 Pages 894-897
    Released: October 05, 2015
    JOURNALS OPEN ACCESS
    Effects of mechanical stress on lithium chemical potential in electrodes and electrolytes for all-solid-state lithium ion batteries were investigated. Dense film electrodes of LiCoO2 or LiMn2O4 were symmetrically deposited on both surfaces of a plate of various solid state lithium ion conductors, such as Li0.29La0.57TiO3, Li7La3Zr2O12 and Li1+x+yAlx(Ti,Ge)2−xSiyP3−yO12. Mechanical stress was applied to the specimen by four points bending tests while measuring electromotive force (EMF) between the two electrodes. EMF proportional to the applied stress was observed. EMF was significantly dependent on the electrode material, but was almost independent of the electrolyte material. These results indicated that lithium chemical potential varied under mechanical stress both in the electrode and electrolyte but the influence of mechanical stress appeared more notably in the electrode than the electrolyte. The lithium chemical potential changes in the electrode and the electrolyte under mechanical stress were discussed based on the idea of local equilibrium.
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  • Ryo HARADA, Keigo ASO, Akitoshi HAYASHI, Masahiro TATSUMISAGO
    Volume 83 (2015) Issue 10 Pages 898-901
    Released: October 05, 2015
    JOURNALS OPEN ACCESS
    All-solid-state cells with LiCoPO4 (LCP) active material with high redox potential of 4.8 V (vs. Li+/Li) were fabricated and the cells operated as a lithium secondary battery at room temperature. The composite electrodes of LCP active material and LiTi2(PO4)3 (LTP) electrolyte with large contact area were synthesized in the media of oleic acid and paraffin wax by heat treatment at 700°C. The prepared LCP-LTP-Acetylene black (AB) composites were applied to electrochemical cells with a conventional organic liquid electrolyte and a sulfide solid electrolyte. The all-solid-state cells using the positive electrode composed of the LCP-LTP-AB composite and the sulfide electrolyte showed the initial discharge capacity of 50 mAh g−1 at 4.8 V (vs. Li+/Li). The cells using the electrodes without LTP and the sulfide electrolyte were difficult to operate, suggesting that formation of close contacts between LCP and LTP, and additional ion conduction paths to LCP-LTP particles are effective in increasing capacities in all-solid-state cells.
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  • Erfu NI, Syota GOTO, Zhen QUAN, Noriyuki SONOYAMA
    Volume 83 (2015) Issue 10 Pages 902-908
    Released: October 05, 2015
    JOURNALS OPEN ACCESS
    Improvement of electrochemical property of K2V8O21, a stable phase of vanadium bronzes, was attempted by redox inactive metal ion doping. From the XRD pattern and lattice parameter change, it was confirmed that Ti and Nb can be exchanged with vanadium until 2 mol%. By doping 1 mol% Nb5+ to K2V8O21, the discharged capacity was improved to 210 mAh/g from 140 mAh/g for non-dope system. In ex-situ XRD measurement, non-dope K2V8O21 became amorphous in the first discharge process. For Nb-doped system, main reflection of K2V8O21 observed after both discharge process and first discharge-charge cycle. The lattice parameter of c axis increased while that of a axis decreased after discharge. Both lattice parameters got back to the initial position after charging process. This result suggests that lithium ions are intercalating into the inter layer part along the c axis during the discharge process. Mechanical mixing active materials with acetylene black was attempted for the further improvement in the electrochemical property. The initial capacity of ball milled Nb-doped K2V8O21 was improved to 315 mAh/g. This result suggests that the capacity of K2V8O21 is determined by the numbers of lithium ion that can be intercalated into the lattice without the destruction of its crystal structure.
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  • Hironobu HORI, Shigeto OKADA
    Volume 83 (2015) Issue 10 Pages 909-913
    Released: October 05, 2015
    JOURNALS OPEN ACCESS
    The reconversion reaction of lithium fluoride (LiF)/iron (Fe) nanocomposite thin film cathodes prepared with the co-deposition method was investigated at room temperature. The LiF:Fe in molar ratio of 1:1 composite thin film was able to be discharged with large capacity of 300 mAh g−1 after the reconversion reaction on the first charge at 25°C. After the 2nd cycle, it showed relatively stable reversible capacity more than 200 mAh g−1. The discharge profile with 2 V plateau was similar to that of ferrous fluoride (FeF2), and the trace of FeF2 was detected in the fully-charged LiF/Fe nanocomposite thin film by X-ray photoelectron spectroscopy (XPS). These results suggest that the reconversion reaction from LiF/Fe to FeF2 proceeded successfully on the first charge as we expected.
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  • Kohei IKEDA, Shoshi TERADA, Toshihiko MANDAI, Kazuhide UENO, Kaoru DOK ...
    Volume 83 (2015) Issue 10 Pages 914-917
    Released: October 05, 2015
    JOURNALS OPEN ACCESS
    The electrochemical properties of a mechanochemically synthesized Li22Sn5 electrode in a solvate ionic liquid-based electrolyte were investigated. The electrolyte was composed of lithium bis(trifluoromethanesulfonyl)amide (Li[TFSA]), tetraglyme (G4), and a hydrofluoroether solvent (HFE) in a molar ratio of 1:1:6.2, in which Li+ and G4 formed a 1:1 complex cation of [Li(G4)]+. The Li22Sn5 electrode exhibited an initial discharge capacity of 500 mA h g−1 in this electrolyte; however, the capacity decreased with increased numbers of charge-discharge cycles. This was attributed to the Li-Sn alloy’s volume change in the electrode during the electrochemical reaction. To examine the behavior of the electrode material in a lithium-sulfur battery, a full cell consisting of a Li22Sn5 anode, S cathode, and [Li(G4)][TFSA]/HFE electrolyte was fabricated. The cell was discharged and charged stably without severe side reactions. The dissolution of lithium polysulfides, reaction intermediates with the sulfur cathode, was effectively suppressed in the electrolyte, leading to efficient charge-discharge cycling of the Li22Sn5-S cell.
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  • Masaki YAMAGATA, Kohei TANAKA, Yoshihiro TSURUDA, Yoshitsugu SONE, Sei ...
    Volume 83 (2015) Issue 10 Pages 918-924
    Released: October 05, 2015
    JOURNALS OPEN ACCESS
    A prototype lithium-ion battery with a bis(fluorosulfonyl)imide (FSI)-based ionic liquid electrolyte was developed. The prototype was mounted on a demonstration module of the “Hodoyoshi-3” microsatellite, which was successfully launched on June 20, 2014. Qualification tests for space application, including radiation tolerance and vacuum tests, revealed negligible degradation of the ionic liquid-based lithium-ion battery (IL-LIB) cell. According to the flight data, the IL-LIB cell can exist stably in an ultra-high vacuum environment despite its thin and flexible pouch casing without any rigid anti-vacuum reinforcements. Furthermore, the power unit showed the same charge–discharge performance as that predicted by the charge–discharge behavior of an identical cell on the ground, suggesting that the IL-LIB cell maintains performance in high vacuum a microgravity environment. These results prove that LIB cells with FSI-based ionic liquids can be used as a power source for space applications.
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