Papers by Keyword: Lithium-Ion

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Authors: Yasuhiro Harada, Yoshitaka Ishikawa, Jun Kuwano, Yasukazu Saito
175
Authors: Masashi Hirakuri, Toyoki Okumura, Morihiro Saito, Jun Kuwano
Abstract: In order to reproduce the observed ionic conductivities and activation energies computationally, the potential parameters (PMs) were optimized for classical molecular dynamic simulations on Li ion conduction in the A-site deficient perovskite solid solution La056Li0.33TiO3 with disordered A-site ion arrangement. By the use of the optimized PMs, the conductivities and the activation energies were improved considerably from 4.1×10-3 Scm-1 to 4.4×10-2 Scm-1 at 800 K and 0.02 eV to 0.2 eV, respectively. The pair correlation functions calculated with the optimized PMs reveal that the Li-ions are located somewhat broadly mainly in the vicinity of the midpoint between the center of the A-site and the center of the bottleneck formed by four O2-, and that the simulated Li location is significantly related to the conductivity.
61
Authors: Toyoki Okumura, Ayumi Dodomi, Morihiro Saito, Jun Kuwano
Abstract: The locations and local environments of the Li ions in La0.56Li0.33TiO3 have been investigated by classical molecular dynamics (MD) simulations and first-principles (FP) calculations. The pair correlation functions of Li-O and Li-Ti indicate that the Li ions are located somewhat broadly mainly in the vicinity of the midpoint between the center of the A-site and the center of the bottleneck formed by four O2-. This is consistent well with that suggested from previous neutron diffraction and 6Li-NMR studies. The FP calculations suggest a different location of the Li ion in the vicinity of the midpoint between the centers of two adjcent bottlenecks; however it coincides with one of the locations shown by the trajectories simulated with the MD calculations.
275
Authors: Itta Komiya, Keisuke Nakao, Kiyofumi Yamagiwa, Jun Kuwano
Abstract: The compositions La0.56Li0.33TiO2.95F0.05•xLiF (x=0-025) were prepared by addition of LiF to the disordered form of the well-known Li ion conductor La0.56Li0.33TiO3. Although the total conductivities improved, there was no change in the bulk conductivity with LiF addition. No reflections due to LiF were observed in their XRD patterns, and the profiles and the chemical shifts of their 19F MAS-NMR resonances were almost the same as those of LiF. The results indicate that no substitution of F takes place, and that the added LiF acts simply as a sintering assistant agent.
229
Authors: Yoshitaka Ishikawa, Yasuhiro Harada, Jun Kuwano
171
Authors: Atsunori Matsuda, Y. Higashi, Kiyoharu Tadanaga, T. Minami, Masahiro Tatsumisago
Abstract: V2O5 microparticles of 0.3-0.6 μm in diameter were prepared from VO(O-C3H7 i)3 in an ethanol solution by the sol-gel method. The addition of poly(ethylene glycol) and acetyl acetone into the sols was effective to control the size and spherical shape of V2O5 particles. The particles thus obtained were amorphous having a layered structure with hydrated water, and transformed into an orthorhombic phase at 500°C through a glassy state. The microparticles were positively charged in I2-containing acetone, so that they were electrophoretically deposited on the cathode with applied DC voltage. The prepared particles were used as a cathode in an electrochemical cell with a lithium metal as an anode. Discharge capacity of a rechargeable cell of Li / LiPF6 (ethylene carbonate + diethylene carbonate) / V2O5 -based composite was 110-180 mAh g-1 when the potential range and current density were 2-4 V and 0.1 mAcm-2, respectively.
107
Authors: Yan Ling Li, Qiang Ru
Abstract: The first-principle calculation method with plane-wave basis and pseudo-potentials was employed to investigate the intercalation/extraction mechanism of lithium in NiSn3Sb4. The insertion/substitution formation energies and the electronic structures of NiSn3Sb4 as well as its lithiated products were studied in order to research the migration path of lithium intercalation. The results show that lithium would firstly occupy interstitial sites, then Ni and Sn atoms are replaced gradually by additional lithium. The dissociated Ni atom can relieve the volume expansion and improve the recycling performance of the crystal. It can be also found that as lithium atoms insert into host material, intense electron transport from Li2s to Sn5p and Sb5p occurs at the Fermi level.
881
Authors: Yuji Hirakoso, Yasuhiro Harada, Jun Kuwano, Yasukazu Saito, Yoshitaka Ishikawa, Tomoyasu Eguchi
209
Authors: Kei Sugiura, Yasuhiro Harada, Jun Kuwano
127
Authors: Yasuhiro Harada, Jun Kuwano, Yasukazu Saito
227
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