Atomic Layer Deposition of Aluminum and Titanium Phosphates

Hämäläinen, Jani; Holopainen, Jani; Munnik, F.; Heikkilä, Mikko; Ritala, Mikko; Leskelä, Markku

doi:10.1021/jp205222g

Cited by 35 publications

(30 citation statements)

References 24 publications

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“…AlPO 4 has been shown to be superior to metal oxides as a coating layer in cathode materials, due to the strong covalency of PO 4 polyanions with the Al 3+ in AlPO 4 [104]. ALD recipes for metal phosphates have been developed [105][106][107]. Other types of potential coating materials are ionic and/or electronic conductors, which are expected to prevent unwanted side reactions and at the same time improve diffusion of lithium ions and/or electrons through the coating layers.…”

Section: Ald Of Surface Engineeringmentioning

confidence: 99%

Elegant design of electrode and electrode/electrolyte interface in lithium-ion batteries by atomic layer deposition

2014

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Lithium-ion batteries (LIBs) are very promising power supply systems for a variety of applications, such as electric vehicles, plug-in hybrid electric vehicles, grid energy storage, and microelectronics. However, to realize these practical applications, many challenges need to be addressed in LIBs, such as power and energy density, cycling lifetime, safety, and cost. Atomic layer deposition (ALD) is emerging as a powerful technique for solving these problems due to its exclusive advantages over other film deposition counterparts. In this review, we summarize the state-of-the-art progresses of employing ALD to design novel nanostructured electrode materials and solid-state electrolytes and to tailor electrode/electrolyte interface by surface coatings in order to prevent unfavorable side reactions and achieve optimal performance of the electrode. Insights into the future research and development of the ALD technique for LIB applications are also discussed. We expect that this review article will provide resourceful information to researchers in both fields of LIBs and ALD and also will stimulate more insightful studies of using ALD for the development of next-generation LIBs.

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Section: Ald Of Surface Engineeringmentioning

confidence: 99%

Elegant design of electrode and electrode/electrolyte interface in lithium-ion batteries by atomic layer deposition

2014

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“…We have recently examined ALD of aluminum and titanium phosphates by using trimethyl phosphate (TMPO) and the corresponding metal halides without any separate oxygen source. 26 In this study we will make a similar approach to lithium phosphate thin films and use TMPO with two lithium precursors, namely lithium tertbutoxide (LiO t Bu) and lithium hexamethyldisilazide [LiHMDS, also known as lithium bis(trimethylsilyl)amide]. Earlier only the lithium bis(ethyldimethylsilyl)amide and diisopropylphosphate combination has been mentioned in the patent literature for ALD of lithium phosphate.…”

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confidence: 99%

Lithium Phosphate Thin Films Grown by Atomic Layer Deposition

Hämäläinen

Holopainen

Munnik

et al. 2012

J. Electrochem. Soc.

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Lithium phosphate, Li 3 PO 4 , has been considered a potential electrolyte material for lithium ion batteries and CO 2 sensors in particular if the films can be made dense and of high quality already at low thickness. In this work, Li 3 PO 4 thin films were deposited by atomic layer deposition (ALD) between 225 and 350 • C using trimethyl phosphate and either of the two lithium sources, namely lithium hexamethyldisilazide or lithium tert-butoxide. The deposited films showed slightly crystalline Li 3 PO 4 structure in X-ray diffraction and the elastic recoil detection analysis confirmed this stoichiometry with some carbon and hydrogen impurities. The crystallinity and thermal stability of the films at elevated temperatures in N 2 were also examined. The long term stability of the deposited Li 3 PO 4 films under ambient air may be an issue for the applicability of these processes. Lithium phosphate, Li 3 PO 4 , can be applied as an electrolyte in solid state lithium ion batteries 1-3 and CO 2 gas sensors. 4-6 Also optical humidity sensors based on Li 3 PO 4 have been presented recently. 7 Thin Li 3 PO 4 film has also been used as an interfacial layer between LiCoO 2 electrode and solid polymer electrolyte in solid state lithium ion battery. 8 Crystallization of Li 3 PO 4 greatly decreases the ionic conductivity: amorphous Li 2.7 PO 3.9 has an ionic conductivity of 6.6 × 10 −8 S/cm while the polycrystalline γ-Li 3 PO 4 has been extrapolated to be highly resistive with as low conductivity as 4.2 × 10 −18 S/cm at 25 • C. 9 Even if the ionic conductivity is only moderate, amorphous Li 3 PO 4 is still a potential electrolyte material provided it can be made dense already at low thickness.In lithium ion battery applications the 3D structuring of the materials would be a way to effectively increase the energy storage capacity by increasing the specific surface area. 10, 11 Atomic layer deposition (ALD) 12-15 may prove to be useful for depositing thin films on demanding 3D structures as films grown by ALD inherently possess good conformality and uniformity because of the alternating, saturative precursor doses and self-limiting surface reactions. The resulting accurate thickness controllability and repeatability of the films is a major benefit of the layer by layer approach used in ALD. Some of the electrolyte material candidates for 3D batteries include for example Li 3 PO 4 and nitrogen mixed lithium phosphate known as LiPON. 10,11 ALD processes for phosphate films are very few in number, although aluminum phosphate thin films have been deposited already in the 90's. 16,17 Besides aluminum phosphate, only ALD of calcium phosphate has been published. 18 Also lithium containing ALD processes were absent until recent reports on ALD of lithium hydroxide, lithium carbonate, lithium aluminate, lithium silicate, lithium lanthanate and lithium lanthanum titanates. [19][20][21][22][23] In addition, ALD of LiFePO 4 and Ca:LaPO 4 materials have been recently presented. 24,25 Here we report ALD growth and characterization of lithium...

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“…) for the LaPO 4 thin film ALD system. The optimization was performed at 275 °C, well inside previously reported ALD windows of lanthanum and phosphate systems using equivalent precursors . When varying the pulsing duration for the precursor under investigation, all other pulse and purge times were kept at 5 s. After optimization, a La(thd) 3 pulse of 1 s was deemed sufficient, whereas TMPO and O 3 /H 2 O pulses were set to 2 s. These pulse durations have been used throughout the remainder of the experiments.…”

Section: Resultsmentioning

confidence: 99%

“…Thin film depositions of phosphates by ALD have not yet been extensively studied. Reports have been made of the deposition of lithium phosphate, iron phosphate, titanium phosphate, and aluminum phosphate . These materials have mainly been studied as potential electrolytes or as cathodes in Li‐ion batteries.…”

Section: Introductionmentioning

confidence: 99%

Atomic Layer Deposition of LaPO₄ and Ca:LaPO₄**

Sønsteby

Østreng

Fjellvåg

et al. 2014

Chemical Vapor Deposition

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Thin films of lanthanum phosphate (LaPO4) are produced by atomic layer deposition (ALD) for the first time, using a precursor combination of (CH3)3PO4, La(thd)3 (Hthd = 2,2,6,6‐tetramethylhepta‐3,5‐dione), H2O, and O3. The deposition process is studied via an in‐situ quartz crystal microbalance (QCM) and found to be a two‐step process in which both water and ozone contribute to the growth. The best results are obtained when both water and ozone are pulsed simultaneously. The growth is self‐limiting by nature, and a stoichiometric LaPO4 phase can be obtained for a 1:1 pulsed ratio of the two precursors. The resulting LaPO4 films are amorphous as deposited, and crystallize to the monoclinic structure after annealing in air for 10 h at 1350 °C. The LaPO4 thin films can also be doped by calcium during growth by replacing some of the La(thd)3 pulses by Ca(thd)2. Films where 4.4% of the lanthanum in LaPO4 is replaced by calcium are obtained.

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Atomic Layer Deposition of Aluminum and Titanium Phosphates

Cited by 35 publications

References 24 publications

Elegant design of electrode and electrode/electrolyte interface in lithium-ion batteries by atomic layer deposition

Elegant design of electrode and electrode/electrolyte interface in lithium-ion batteries by atomic layer deposition

Lithium Phosphate Thin Films Grown by Atomic Layer Deposition

Atomic Layer Deposition of LaPO₄ and Ca:LaPO₄**

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Atomic Layer Deposition of Aluminum and Titanium Phosphates

Cited by 35 publications

References 24 publications

Elegant design of electrode and electrode/electrolyte interface in lithium-ion batteries by atomic layer deposition

Elegant design of electrode and electrode/electrolyte interface in lithium-ion batteries by atomic layer deposition

Lithium Phosphate Thin Films Grown by Atomic Layer Deposition

Atomic Layer Deposition of LaPO4 and Ca:LaPO4**

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Atomic Layer Deposition of LaPO₄ and Ca:LaPO₄**