Rapid Charge–Discharge Property of Li₄Ti₅O₁₂–TiO₂ Nanosheet and Nanotube Composites as Anode Material for Power Lithium-Ion Batteries

Abstract

Well-defined Li4Ti5O12-TiO2 nanosheet and nanotube composites have been synthesized by a solvothermal process. The combination of in situ generated rutile-TiO2 in Li4Ti5O12 nanosheets or nanotubes is favorable for reducing the electrode polarization, and Li4Ti5O12-TiO2 nanocomposites show faster lithium insertion/extraction kinetics than that of pristine Li4Ti5O12 during cycling. Li4Ti5O12-TiO2 electrodes also display lower charge-transfer resistance and higher lithium diffusion coefficients than pristine Li4Ti5O12. Therefore, Li4Ti5O12-TiO2 electrodes display lower charge-transfer resistance and higher lithium diffusion coefficients. This reveals that the in situ TiO2 modification improves the electronic conductivity and electrochemical activity of the electrode in the local environment, resulting in its relatively higher capacity at high charge-discharge rate. Li4Ti5O12-TiO2 nanocomposite with a Li/Ti ratio of 3.8:5 exhibits the lowest charge-transfer resistance and the highest lithium diffusion coefficient among all samples, and it shows a much improved rate capability and specific capacity in comparison with pristine Li4Ti5O12 when charging and discharging at a 10 C rate. The improved high-rate capability, cycling stability, and fast charge-discharge performance of Li4Ti5O12-TiO2 nanocomposites can be ascribed to the improvement of electrochemical reversibility, lithium ion diffusion, and conductivity by in situ TiO2 modification.

Fabrication of Li4Ti5O12-TiO2 Nanosheets with Structural Defects as High-Rate and Long-Life Anodes for Lithium-Ion Batteries

“…For LTO-AT-RT-500, not only the peak at 25.3° becomes shaper, but also additions peaks at 37.3° and 48.1° appear. All these three peaks can be assigned to the three strongest peaks of anatase-TiO 2 22 . Meanwhile, the peaks of rutile-TiO 2 can be observed at 27.5 and 54.3° 24 .…”

“…With a decrease in the molar ratio of Li/Ti to 4.2:5 (LTO-RT-AT), two weak peaks at 25.26° and 27.39° arise in Fig. 1c, which can be indexed as the typical peaks of anatase-TiO 2 and rutile-TiO 2 22, 23 , respectively, indicating a ternary-phase composite consisting of dominant LTO and a low amount of rutile-TiO 2 and anatase-TiO 2 was obtained. When the ratio further drops to 4:5 (LTO-RT), the peak of anatase-TiO 2 completely disappears and the peaks of rutile-TiO 2 increase further, indicating that a dual-phase composite including LTO and rutile-TiO 2 was obtained.…”

Porous Li4Ti5O12–TiO2 nanosheet arrays for high-performance lithium-ion batteries

“…Amongst them, the voltage gap between the redox peaks for the 0.5-LTO-TO-700 electrode is remarkably wider than other two, indicating more polarization associated with Li + insertion/extraction in this sample. [17] Nevertheless, the position of the redox peaks for the TiO 2 located around 1.68 V and 2.20 V is kept the same for the three samples corresponding to the Equation 2. It is noteworthy that the 0.5-LTO-TO-600 electrode exhibits the highest current density among the three samples, demonstrating the lowest ionic and electrical resistance of this sample.…”

Synthesis and electrochemical performance of Li4Ti5O12/TiO2/C nanocrystallines for high-rate lithium ion batteries

“…[7][8][9] Therefore, searching for alternative anode materials with excellent rate-capability and good safety property becomes the urgent topic for the LIBs field. However, the carbonaceous materials have some safety concerns, particularly when used for high power batteries.…”