The changes of Li+/vacancy arrangement in Li2+xTi3O7 with a ramsdellite-type

structure upon topo-electrochemical Li+ insertion were investigated by the entropy

measurement of reaction combined with the Monte Carlo simulation. The

experimental entropy measurement was conducted by potentiometric and

calorimetrical methods. The obtained experimental data were in good accordance

with simulated results. The results indicated that the ordered Li+/vacancy

arrangement appeared at the approximate compositions of x = 0.45 and 1.20, where

the observed entropy of reaction humped. The ordering of Li/vacancy were also

indicated at the approximate compositions of x = 0.24 and 1.16 in Li2+xTi3O7 by the

Monte Carlo simulation which considers the most stable Li/vacancy arrangement in

terms of Coulombic interaction. This substantial agreement between

electrochemical behaviours and computational results confirmed that the formation

of superstructure arising from Li/vacancy arrangement during the electrochemical

reaction deeply related to the atomic level Coulombic interactions.

Relationship Between Electrochemical Behaviour and Li/Vacancy Arrangement in

Ramsdellite Type Li2+xTi3O7. W.Cho, T.Kashiwagi, W.Ra, M.Nakayama,

M.Wakihara, Y.Kobayashi, H.Miyashiro: Electrochimica Acta, 2009, 54[6], 1842-

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