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The formation mechanism of Li₄Ti₅O_12-y solid solutions prepared by carbothermal reduction and the effect of Ti³⁺ on electrochemical performance.

ABSTRACT: Samples of Li₄Ti₅O_12-y solid solutions are synthesized by one-step solid-state carbothermal reduction reaction using Li₂CO₃, anatase, and carbon black under a nitrogen atmosphere. The underlying formation mechanism that leads to Li₄Ti₅O_12-y solid solutions is proposed. The formation mechanism of the Li₄Ti₅O_12-y solid solution is investigated by in situ variable temperature X-Ray diffraction (VT-XRD) and thermogravimetric analysis/differential scanning calorimetry (TGA-DSC). First, some Ti⁴⁺ centers are converted to Ti³⁺ (TiO₂-TiO_2-x) because of the presence of carbon black. Secondly, Li₂CO₃ reacts with TiO_2-x (anatase) to form Li₂TiO₃. Thirdly, Li₂TiO₃ reacts with TiO_2-x to form the Li₄Ti₅O_12-y solid solution, while anatase starts to transform into rutile at the same time. Rutile reacts with Li₂TiO₃ to form Li₄Ti₅O_12-y at higher temperatures. The presence of Ti³⁺ not only improves the electrical conductivity but also improves the ionic conductivity. As a result, the as-prepared material exhibits good rate capability and cycling stability with 99.3% capacity retention after 200 cycles.

SUBMITTER: Yang G

PROVIDER: S-EPMC6423044 | biostudies-literature | 2019 Mar

REPOSITORIES: biostudies-literature

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The formation mechanism of Li4Ti5O12-y solid solutions prepared by carbothermal reduction and the effect of Ti3+ on electrochemical performance.

Yang Guijun G Park Soo-Jin SJ

Scientific reports 20190318 1

Samples of Li4Ti5O12-y solid solutions are synthesized by one-step solid-state carbothermal reduction reaction using Li2CO3, anatase, and carbon black under a nitrogen atmosphere. The underlying formation mechanism that leads to Li4Ti5O12-y solid solutions is proposed. The formation mechanism of the Li4Ti5O12-y solid solution is investigated by in situ variable temperature X-R ...[more]

PMID: 30886218

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The formation mechanism of Li₄Ti₅O_12-y solid solutions prepared by carbothermal reduction and the effect of Ti³⁺ on electrochemical performance.

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The formation mechanism of Li<sub>4</sub>Ti<sub>5</sub>O<sub>12-y</sub> solid solutions prepared by carbothermal reduction and the effect of Ti<sup>3+</sup> on electrochemical performance.

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