Investigation of lithium diffusion in nano-sized rutile TiO2 by impedance spectroscopy

High specific capacity of TiO2-graphene nanocomposite as an anode material for lithium-ion batteries in an enlarged potential window

“…Because NH 3 ·H 2 O is a high volatile liquid and EG is not a good solvent for NH 3 , the reaction between NH 3 and Ti 4+ was limited at the gas/liquid interface [41,42]. Then the produced Ti(OH) 4 could be quickly decomposed to TiO 2 at 180 • C (Eqs. (1) and (2)).…”

“…At the room temperature, the two solutions were separated by the beaker. At the elevated reaction temperature (180 • C), evaporated ammonia reacted with Ti 4+ at the gas/liquid interface to produce Ti(OH) 4 , which in situ deposited onto the graphene sheets. Because NH 3 ·H 2 O is a high volatile liquid and EG is not a good solvent for NH 3 , the reaction between NH 3 and Ti 4+ was limited at the gas/liquid interface [41,42].…”

“…Briefly, in a 20 mL beaker, 0.7589 g of TiCl 4 (Tianjin Kermel Chemical Reagent Co., Ltd., China) was dissolved in 20 mL of ethylene glycol (EG) (Beijing Chemical Reagent Co., Ltd., China), and then 0.0983 g of graphene sheets was added and sonicated for 10 h to yield a homogeneous suspension. Then the beaker was placed into a 100 mL Teflon-lined autoclave with 14 mL of ammonia solution (Guangzhou Chemical Reagent Factory, China).…”

“…TiO 2 has been regarded as a promising anode material for lithium-ion batteries due to its structural characteristics, low cost, safety and environmental benignity [1][2][3]. However, its practical capacity and high-rate capability are limited due to the low Li-ion diffusivity and electronic conductivity during reversible Li-ion insertion/extraction process [4][5][6]. In order to improve the electrochemical performance of TiO 2 materials, nanotechnology has been explored to provide increased reaction active sites and short diffusion lengths for electron and Li-ion transport [7][8][9][10][11][12][13].…”

β-NMR of 8Li+ in rutile TiO2

“…md and dft calculations also predict fast, anisotropic 1D diffusion of Li + along the rutile c-axis with a low hopping-barrier of ∼ 0.05 eV [21,22,24,25]. 3 These barriers are significantly lower than what is observed experimentally from macroscopic methods [26,27], though such measurements are done far from the limit of infinitely dilute lithium, where the potential energy landscape is likely altered by lattice distortions and Li + -Li + interactions [22,28]. The broad component of the resonance may be due to fast-diffusion of 8 Li + to Frenkel pairs, formed from irradiation, before they heal.…”