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  • Author or Editor: H. Ikuta x
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Abstract  

The enthalpy of formation for LiMyMn2–yO4 (M=Co, Cr, Li, Mg, Ni) was measured by a Tian-Calvet type high temperature isothermal microcalorimeter. The standard enthalpy of formation for LiMn2O4 at 876 K was evaluated to be H f 0=–1404.2±6.4 kJ mol–1. The partial substitution of Co and Ni for Mn decreased the absolute H f 0 value, while that of Cr and Mg for Mn increased the absolute H f 0 value. In the case of the partial substitution of Li for Mn, no marked change in H f 0 could be observed.

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Journal of Thermal Analysis and Calorimetry
Authors: M. Tachibana, T. Tojo, H. Kawaji, T. Atake, N. Morita, H. Ikuta, Y. Uchimoto, and M. Wakihara

Abstract  

Heat capacity of spinel LiCr1/6Mn11/6O4-d (d=0, 0.0184)was measured between 5 and 300 K. Both compounds showed no anomaly in the measured temperature range, especially around the room temperature where a structural phase transition is reported for the parent compound LiMn2O4. The non-stoichiometric compound LiCr1/6Mn11/6O3.9816 has greater heat capacity than that of the stoichiometric LiCr1/6Mn11/6O4. Molecular dynamics study on the vibrational property of LiMn2O4-d revealed that the lattice defects in the non-stoichiometric compound increase the low frequency phonons compared with the stoichiometric compound. It should be related to the greater heat capacity of the non-stoichiometric compound LiCr1/6Mn11/6O3.9816.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: S. Mitsuoka, H. Ikezoe, T. Ikuta, S. Hamada, Y. Nagame, K. Tsukada, I. Nishinaka, and T. Ohtsuki

Abstract  

In order to separate rare fusion evaporation residues from the primary beam in flight, a recoil mass separator has been constructed at the JAERI tandem-booster facility. By using the recoil mass separator, new neutron-deficient isotopes209Th and212Pa have been produced. After a brief facility description, some recent experimental results are presented.

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Abstract  

We have focused on the poly(ethylene glycol) (PEG)-borate ester as a new type plasticizer for solid polymer electrolyte for lithium ion secondary battery. Adding the PEG-borate ester into the electrolyte shows the increase in the ionic conductivity of the polymer electrolyte. By measuring the glass-transition temperature of the polymer electrolytes with DSC, it is found that the increase in ionic conductivity of the polymer electrolyte is due to the increase in ionic mobility. By investigating the temperature dependence of the ionic conductivity of the polymer electrolytes using William-Landel-Ferry type equation, we considered that the PEG-borate ester does not have any influence for dissociation of Li-salt.

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