Li and Na-ion diffusion and intercalation characteristics in vertically aligned TiS₂ nanowall network grown using atomic layer deposition

Abstract

We present here the study of diffusion and intercalation mechanisms of Li-ion and Na-ion in titanium disulfide (TiS 2 ) films grown by atomic layer deposition (ALD). The layered TiS 2 has been explored here due to the interesting differences between the intercalation mechanisms of Li + and Na + . The ALD grown TiS 2 films further facilitate the study as this method provides compact and dense films with no polymer binder and carbon additives. The diffusion and intercalation processes are observed to depend on the ionic size and character of the solid electrolyte interphase. The increased capacity obtained for the present ALD synthesized samples is attributed to the enhanced anchoring ability of the TiS 2 films, which comprises of an extended nanowall network. The charge transfer resistance (R ct ) obtained from impedance data correlate well with the lithiation steps observed in the galvanostatic discharge-charge studies. At potentials where lithiation takes place, R ct value is observed to drop. This direct correlation is however, not observed between the R ct and sodiation potential. The diffusion coefficients, calculated using GITT and impedance methods, are observed to be independent of the type of Li-salts. However, the variation of diffusion coefficients with the lithiation/sodiation voltages are different. This is attributed to the combined differences in the ionic radii and phase formation. Intercalation-de-intercalation in to TiS 2 coated with alumina is also studied here. Coating with alumina results in a stable SEI. However, coating leads to higher R ct , lower D Li+ and poor capacity retention as a function of cycle number.

High Formability and Fast Lithium Diffusivity in Metastable Spinel Chloride for Rechargeable All‐Solid‐State Lithium‐Ion Batteries

“…Here, the conductivity at 30 °C was about 40 times higher than that of the room‐temperature orthorhombic phase of LFC, which was calculated to have a diffusion coefficient of 2.8 × 10 −10 cm 2 s −1 by the Nernst–Einstein equation. [ 46 ] The value was compared with other diffusion coefficients of the orthorhombic LFC and some representative cathode materials for Li‐ion batteries, [ 47–51 ] as shown in Table 1 . Note that the chemical diffusion coefficient measured for thin‐film electrodes, not for composite electrodes, are only selected in Table 1 for comparison purposes considering the Haven ratio.…”

Atomic Layer Deposition of 2D Metal Dichalcogenides for Electronics, Catalysis, Energy Storage, and Beyond

“…Sayed et al. [ 255 ] have studied diffusion and intercalation mechanisms of Li + and Na + ions into rough ALD TiS 2 films. The first cycle discharge capacities of both Li + and Na + ions, ≈750 and 450 mAh g −1 , respectively, were lower compared to most of the MoS 2 and WS 2 anodes discussed here but still higher than that of graphite, for example.…”

“…Tens of nm rough films (50 nm) LIB, NIB [255] Ti(NMe 2 ) 4 + H 2 S 150-180 ≈5-100 nm films (amorp., oxidizes) - [256] 100 ≈30 nm rough film (cryst.) - [257] Ti(NMe 2 ) 4 + H 2 S plasma 150-200 ≈30 nm rough film (≈50-100 nm) - [257] WS 2 WCl 6 + H 2 S e) 390 a few-10 ML (cryst.)…”

Tortuosity Modulation toward High‐Energy and High‐Power Lithium Metal Batteries

“…Consequently, the VO 2 cathode achieved a high specific capacity (444.2 mAh g −1 at 50 mA g −1 ), superior rate capability (156.7 mAh g −1 at 2000 mA g −1 ), and stable cycle life (900 cycles, Figure 8d–f). Low‐tortuous cathodes such as LFP walls, [ 104 ] LFP nanoarrays, [ 105 ] LiCoO 2 nanorods, [ 106 ] LiCoO 2 nanowires, [ 107 ] V 2 O 5 nanoneedle arrays, [ 108 ] FeF 2 walls, [ 109 ] and TiS 2 nanowalls [ 110 ] have also been developed via glancing angle deposition, stacked LiCoO 2 /graphite sheets cosintering approach, solvothermal method, and atomic layer deposition, to improve their energy densities and rate capacities.…”