Atomic layer deposition of LixTiyOz thin films

Miikkulainen, Ville; Nilsen, Ola; Laitinen, Mikko; Sajavaara, Timo; Fjellvåg, Helmer

doi:10.1039/c3ra40745d

Cited by 54 publications

(73 citation statements)

References 27 publications

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“…Carbon atoms are common impurities affecting the passivation quality of Al2O3 layers [5,7,8], and are considered harmful for surface passivation. Although ozone possesses a stronger oxidation potential than water, and has potentially beneficial effect on the reduction of impurity concentrations, as shown in previous studies [5,[8][9][10], other studies have also reported relatively high carbon concentration in ozone-based ALD films [11,12]. Despite this possible drawback, ozone-based ALD Al2O3 shows promising surface passivation quality [6,13].…”

Section: Introductionmentioning

confidence: 92%

Effect of ozone concentration on silicon surface passivation by atomic layer deposited Al2O3

Gastrow

Putkonen

et al. 2015

Applied Surface Science

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Section: Introductionmentioning

confidence: 92%

Effect of ozone concentration on silicon surface passivation by atomic layer deposited Al2O3

Gastrow

Putkonen

et al. 2015

Applied Surface Science

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“…The films were amorphous as determined with X-ray diffraction and showed only very small amounts of lithium in ERDA measurements. In contrast, when using Ti(O i Pr) 4 as the titanium source and applying a long pulse time for this precursor, uniform titanate films with higher lithium contents could be deposited [99]. These films also reacted with air, however the reaction was much slower than when using TiCl 4 as the titanium precursor.…”

Section: Methodsmentioning

confidence: 91%

“…In both cases, LiO t Bu was used as the lithium source and water was used as the oxygen source. Titanate films deposited using TiCl 4 reacted rapidly in air [99]. The films were amorphous as determined with X-ray diffraction and showed only very small amounts of lithium in ERDA measurements.…”

Section: Methodsmentioning

confidence: 99%

“…These nanotubes also showed excellent capacity retention. Attempts on the deposition of lithium titanate spinel, Li 4 Ti 5 O 12 , have been made using both titanium tetrachloride TiCl 4 [99] and titanium tetra-iso-propoxide Ti(O i Pr) 4 as precursors [99][100][101]. In both cases, LiO t Bu was used as the lithium source and water was used as the oxygen source.…”

Section: Methodsmentioning

confidence: 99%

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Metal Fluorides as Lithium-Ion Battery Materials: An Atomic Layer Deposition Perspective

2018

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Lithium-ion batteries are the enabling technology for a variety of modern day devices, including cell phones, laptops and electric vehicles. To answer the energy and voltage demands of future applications, further materials engineering of the battery components is necessary. To that end, metal fluorides could provide interesting new conversion cathode and solid electrolyte materials for future batteries. To be applicable in thin film batteries, metal fluorides should be deposited with a method providing a high level of control over uniformity and conformality on various substrate materials and geometries. Atomic layer deposition (ALD), a method widely used in microelectronics, offers unrivalled film uniformity and conformality, in conjunction with strict control of film composition. In this review, the basics of lithium-ion batteries are shortly introduced, followed by a discussion of metal fluorides as potential lithium-ion battery materials. The basics of ALD are then covered, followed by a review of some conventional lithium-ion battery materials that have been deposited by ALD. Finally, metal fluoride ALD processes reported in the literature are comprehensively reviewed. It is clear that more research on the ALD of fluorides is needed, especially transition metal fluorides, to expand the number of potential battery materials available.

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“…[14][15][16][17] For the case of conformal coatings, though, only a few publications demonstrating direct ALD of Li 4 Ti 5 O 12 are available. 18,19 Unfortunately, the electrochemical properties of these films were not tested. The ALD of complex oxides; i.e.…”

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confidence: 99%

Continuous and Conformal Lithium Titanate Spinel Thin Films by Solid State Reaction

Labyedh

Put

Mel

et al. 2018

J. Electrochem. Soc.

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In this work, we report on the fabrication of continuous and uniform thin films by a solid state reaction. The fabrication of spinel Li 4 Ti 5 O 12 thin films was demonstrated by solid state reaction between TiO 2 and Li 2 CO 3 stacked-layers upon thermal annealing. The TiO 2 layer was prepared by physical vapor deposition or atomic layer deposition, whereas the Li 2 CO 3 layer was deposited by chemical solution deposition or atomic layer deposition. The solid state reaction and obtained material properties were investigated on planar substrates. It was found that continuous films with crystalline and stoichiometric Li 4 Ti 5 O 12 can be formed by solid state reaction at temperatures higher than 650 • C. The prepared films exhibited Li-ion intercalation characteristics for Li 4 Ti 5 O 12 spinel with the typical flat plateau at 1.55 V (vs Li + /Li) for both charging and discharging. The theoretical capacity of 612 mAh cm −3 was obtained at slow charging rate of 0.1 C with still 45% capacity attainable at 20 C. Interestingly, it was found that the kinetics is strongly dependent on the current collector substrate used. Solid state reactions (SSR) are a common practice for making powder material. LTO particles, for example, can be synthesized by a solid state reaction between Li 2 CO 3 or LiOH and TiO 2 powders at high temperatures exceeding 800• C for 4-12 hours. 1-3 However, the fabrication of "continuous" and "uniform" thin films by solid state reaction between two superposed thin-films has to our knowledge not been shown so far. In fact, agglomeration and non-continuous nanoparticle coatings are expected after annealing of thin-films, and nanostructures in general, at high temperatures. For example, ZnAl 2 O 4 spinel nanoparticle chains were formed from ZnO nanowires coated with a thin Al 2 O 3 film. 4 In this work, we do show that solid state reactions (SSR) can be used also for continuous and uniform thin films under well controlled conditions. Spinel Li 4 Ti 5 O 12 thin-films of 50 nm were fabricated by SSR between superposing TiO 2 and Li 2 CO 3 thin films. Lithium titanate (Li 4 Ti 5 O 12 or LTO) is a known negative electrode material for high rate lithium ion batteries, but also has been suggested as protective coatings for cathodes.5-10 Thin-films of LTO up to a few tens of nanometer thick coated around cathode particles are sufficiently conductive, both for Li-ions and electrons, while its chemical inertness provides protection against dissolution (e.g. for Mn-based cathodes such as LiMn 2 O 4 (LMO), LiNi x Co 1−2x Mn x O 2 (1/3 ≤ x ≤ 1/2) (NMC)), and parasitic reaction with the electrolyte (controlled formation of interface layers at LTO). Additionally, continuous thin-film LTO coatings are of interest for thin film microbatteries where the electrodes are coated as a thin film on micro-or nanostructured (3D) current collector substrates. Thin film electrodes have direct contact with the underlying current collector and thus guarantee short diffusion path for both the Li-ion and the electrons, hence lead...

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Atomic layer deposition of LixTiyOz thin films

Cited by 54 publications

References 27 publications

Effect of ozone concentration on silicon surface passivation by atomic layer deposited Al2O3

Effect of ozone concentration on silicon surface passivation by atomic layer deposited Al2O3

Metal Fluorides as Lithium-Ion Battery Materials: An Atomic Layer Deposition Perspective

Continuous and Conformal Lithium Titanate Spinel Thin Films by Solid State Reaction

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