Observation of the structural changes of sol-gel formed Li₂MnTi₃O₈during electrochemical reaction by in-situ and ex-situ studies

10 January 2015

Wei Chen

Hanfeng Liang

Lianyi Shao

Jie Shu

Zhoucheng Wang

Abstract

In this work, spinel Li₂MnTi₃O₈is successfully prepared by using a simple sol-gel route and evaluated as an anode material for lithium-ion batteries. Charge-discharge tests exhibits than spinel Li₂MnTi₃O₈can deliver an initial discharge capacity of 273.5 mAh g⁻¹and the reversible capacity is kept at 206.1 mAh g⁻¹after 50 cycles, corresponding to 94.5% of the initial charge capacity. The electrochemical reaction mechanism between Li₂MnTi₃O₈and lithium is investigated based on the results of various in-situ and ex-situ observations. The result indicates that the (Li_0.505Mn_0.495)^tet(Li_0.495Mn_0.005)^octTi_1.5^octO₄has multiple interstitials to accommodate lithium ions during the lithiation process, in which the octahedral sites (4a) would be occupied by lithium ions at high working potential and the tetrahedral sites (8c) would be occupied by lithium ions at low working potential. As a result, two two-phase transitions between three end-number phases Li₂MnTi₃O₈, Li₃MnTi₃O₈and Li₅MnTi₃O₈can be observed during the reversible electrochemical reaction between Li₂MnTi₃O₈and lithium.

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