American Chemical Society
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Synthesis and Electrochemical Performance of C‑Base-Centered Lepidocrocite-like Titanates for Na-Ion Batteries

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journal contribution
posted on 2018-08-02, 17:18 authored by Akihiro Katogi, Kei Kubota, Kuniko Chihara, Koji Miyamoto, Tatsuya Hasegawa, Shinichi Komaba
Lepidocrocite-like titanate, Na0.9[Ti1.7Li0.3]­O4, having a C-base-centered lattice (C-type) is prepared by dehydration of Na0.9[Ti1.7Li0.3]­O4·nH2O having a primitive lattice (P-type) and influence of the interlayer water on its electrochemical performance is examined in nonaqueous Na cells. Upon heating up to 350 °C, P-type Na0.9[Ti1.7Li0.3]­O4·nH2O transforms into the anhydrous C-type phase as a result of gradual removal of the interlayer water. The C-type Na0.9[Ti1.7Li0.3]­O4 delivers reversible capacity of 120 mAh g–1 between 2.0 and 0.1 V vs Na with high Coulombic efficiency at an initial cycle and good capacity retention over 50 cycles. Structural change of the C-type phase during sodiation is investigated by using operando X-ray diffraction measurement.