Effect of Li+ ion mobility on the grain boundary conductivity of Li2TiO3 nanoceramics

Abstract

Lithium titanate (Li 2 TiO 3 ) is one of the most promising candidates among the tritium breeding materials because of its good tritium release capacity. Li concentration has much significance on the diffusivity of tritium in the material. The nanocrystalline single-phase Li 2 TiO 3 with monoclinic structure has been prepared by high energy ball milling followed by calcination at 700 ℃ for 2 h. The field emission scanning electron microscopy (FESEM) studies confirmed uniform distribution of nanocrystalline phase with particle size below 100 nm. The study of the Li + ion diffusion on the sintered sample was investigated by means of electrical conductivity measurements. Electrical properties of the samples were studied in wide temperature (50-500 ℃) and frequency (100 Hz-1 MHz) ranges. The complex impedance spectroscopy (CIS) studies showed the presence of both bulk and grain boundary effects in nanocrystalline Li 2 TiO 3 . The bulk resistance of the samples has been observed to decrease with rise in temperature showing a typical negative temperature coefficient of resistance (NTCR) behavior. The low activation energies of the samples suggested the presence of singly ionized oxygen vacancies in the conduction process. The hopping frequency shifted toward higher frequency with increase in temperature. Activation energy of 0.86 eV was calculated from AC conductivity.

Transport Properties of Nanostructured Li2TiO3 Anode Material Synthesized by Hydrothermal Method

“…The asymmetric broadening of the peaks indicates the spread of relaxation time in the sample. Our data match well with the results reported in the literature [37,38,68]. The ac response obeys the power law [69]:…”

“…Activation Energy (eV) Ref. 7 Li NMR, a.c. conductivity 0.47-0.80 [89] a.c. conductivity 0.81-0.91 [90] electrical conductivity 0.60-0.90 [37] 6,7 Li NMR 0.27 [74] periodic quantum−chemical DFT 0.44-0.54 [75] complex impedance 0.77/0.88 [38] d.c. conductivity 0.86 [68] 6,7 Li NMR 0.52 [91] atomistic simulation 0.51 [92] DFT calculations 0.76 [93] a.c. conductivity 0.65/0.71 this work…”

Comparison of fresh and aged lithium iron phosphate cathodes using a tailored electrochemical strain microscopy technique

“…The ESM signal, which we observe on carbon-coated LFP, is not only limited to structural boundaries within one single grain, which are known to exhibit a high mobility for ions due to structural disordering, high concentration of defects and lower energy barrier [40,54,55]. We also observe a homogeneous high signal on planar locations inside the particle.…”

A Comprehensive Study on Li4si1-xtixo4 Ceramics for Advanced Tritium Breeders

“…Tritium diffusion process can be envisaged as lithium-ion migration which acts as the charge carrier in the ceramics [22,31], the tritium release behavior can be evaluated by measuring the conductivity of breeder materials. Fig.…”

“…Li [7][8][9], mixed-phase ceramics represented by Li 2 TiO 3 /Li 4 SiO 4 [10][11][12][13], oxides modified ceramics [14][15][16] and hetero-element doped ceramics (notably Li 4+x Si 1-x Al x O 4 ) were prepared in recent years [17][18][19][20]. And previous studies have shown that Al doped lithium orthosilicate exhibits the enhanced crushing strength [17,19,20], thermal and ionic conductivity [17,[20][21][22], and tritium release performance [18].…”