Nanocrystalline AlySn1-yO2-y/2 (y = 0.57, 0.4) was investigated as electrode material for lithium-ion batteries. Specific discharge capacities of about 400 mAh g(-1) were obtained for 100 cycles in the case of higher Al content. Electrochemical Li insertion/removal was studied by X-ray diffraction and Li-7/Al-27/Sn-119 nuclear magnetic resonance as well as Sn Mossbauer spectroscopy for different Li contents. The formation of a ternary Li-Al-O matrix stabilizes the active Sn metal particles and prevents degradation during alloying with Li. (C) 2012 Elsevier B.V. All rights reserved.