Lanthanum tungstates with a La/W atomic ratio between 6 and 4.8 have been synthesized as polycrystalline materials using the freeze-drying wet-chemical precursor method. Our results show that a single phase material is obtained when the La/W ratio is between 5.3 and 5.7 (T = 1500 degrees C). Outside this compositional range, segregation of either La(2)O(3) (La/W > or = 5.8) or La(6)W(2)O(15) (La/W < or = 5.2) are found. We have solved the crystal structure for the composition with a La/W nominal atomic ratio of 5.6 by combining powder X-ray and powder neutron diffraction techniques. This structure substantially differs from that previously reported for Ln(6)WO(12) (Ln = Y, Ho). The main differences between the two structure types are the crystal symmetry, the different coordination environment of the cations and the formula unit. The formula unit can be written as La(6.63)W(1.17)O(13.43) (Z = 4; calculated density = 6.395 g/cm(3)), well in accordance with the diffraction techniques, He-pycnometry and electron probe microanalysis. These materials can be described as a face centred cubic structure with space group F43m. Lattice parameters vary between 11.173 and 11.188 A, depending on composition. Dense ceramic materials are obtained at 1400 degrees C, and microanalyses measurements indicate that no significant tungsten evaporation occurs compared to the nominal values. Compositions with La(2)O(3) segregation show similar conductivity values as the single phase ones, but those containing segregation of W-rich phases show a considerable drop in conductivity with increasing content of the secondary phase.

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Energy and power densities of all-solid-state lithium ion batteries can be improved by moving from planar battery structures to three-dimensional structures. Atomic layer deposition (ALD) is a very suitable technique for fabrication of such three-dimensional battery structures. The solid-state electrolyte material lithium lanthanum titanate (LLT) that we have previously made by ALD is unstable in direct contact with many anode materials, and therefore, Li 2 OÀAl 2 O 3 is proposed as a barrier material between the anode and the LLT electrolyte. The deposition of Li 2 OÀAl 2 O 3 thin films by ALD has been accomplished by combining ALD processes for lithium oxide/hydroxide and aluminum oxide. The surface layer composition of the obtained films is Li 2.2 Al 1.0 O z as analyzed by X-ray photoelectron spectroscopy (XPS) while the composition of the bulk film as dissolved in 10% HNO 3 is Li 1.6 Al 1.0 O z as analyzed by inductively coupled plasma mass spectroscopy (ICP-MS). The growth mechanisms of Li 2 OÀAl 2 O 3 films were studied by quartz crystal microbalance (QCM). The QCM data indicates that some absorbed water is left inside the films and that the absorbed water reacts with the metal precursor during subsequent pulses. The amount of absorbed water is reduced when the purge time after the water pulse is increased. Even if there is a contribution of absorbed water to the film growth, the growth saturates to about 2.8 Å/cycle and the film thickness increases linearly with increasing number of deposition cycles.