We prepared thick and dense-crystalline LiNi1/3Co1/3Mn1/3O2 (NMC) composite films at room temperature that can work well as cathodes in all-solid-state battery cells. The thick films were fabricated by aerosol deposition using NMC powder (D50=10.61 m) as a source material. Commercially-obtained NMC powder did not form films at all on silicon wafer substrates, and cracking of the substrates was observed. However, a few tens of nanometer coating with amorphous niobium oxide resulted in the deposition of 7 m-thick crystalline dense composite films. The films were successfully fabricated also on Li +-conductive glass-ceramic sheets with 150 m in thickness, and all-solid-state batteries were fabricated. The solid-state battery provided a cathode-basis discharge capacity of 152 mAh g-1 (3.0-4.2 V, 0.025 C, 333 K) and repeated charge-discharge cycles for 20 cycles.

Aluminum nitride (AlN) powders were synthesized by gas reduction–nitridation of γ‐Al2O3 using NH3 and C3H8 as the reactant gases. AlN was identified in the products synthesized at 1100°–1400°C for 120 min in the NH3–C3H8 gas flow confirming that AlN can be formed by the gas reduction–nitridation of γ‐Al2O3. The products synthesized at 1100°C for 120 min contained unreacted γ‐Al2O3. The 27A1 MAS NMR spectra show that Al–N bonding in the product increases with increasing reaction temperature, the tetrahedral AlO4 resonance decreasing prior to the disappearance of the octahedral AlO6 resonance. This suggests that the tetrahedral AlO4 sites of the γ‐Al2O3 are preferentially nitrided than the AlO6 sites. AlN nanoparticles were directly formed from γ‐Al2O3 at low temperature because of this preferred nitridation of AlO4 sites in the reactant. AlN nanoparticles are formed by gas reduction–nitridation of γ‐Al2O3 not only because the reaction temperature is sufficiently low to restrict grain growth, but also because γ‐Al2O3 contains both AlO4 and AlO6 sites, by contrast with α‐Al2O3 which contains only AlO6.

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Gas reduction-nitridation (GRN), which uses a mixture of NH 3 and carbohydrate as a reactant gas, has been proposed a synthetic technique for producing high-purity nitride powders. In this study, b-SiAlON powder was produced from zeolite using GRN. Zeolite was used directly as the raw material without previous preparation or handling. It was found that high purity b-SiAlON nanopowder was synthesized at 1400°C for 60 min. Furthermore, pure b-SiAlON was successfully produced, containing no minor phases, by the optimization of nitridation, that is, of concentration of C 3 H 8 and the timing of its introduction.