Nanosize silver and tin dioxide powders were synthesised by a novel reverse micelle technique. The reverse micelles were formed from a microemulsion of organic solvents, water based salts and surfactants. The spherical nanosize Ag powders were formed via in situ reduction. The tin hydroxide precipitates were formed in reverse micelles and converted to tin dioxide nanopowders after heat treatment. The Ag and SnO2 powders have a particle size in the range of 20--50 nm. The as-prepared nanosize Ag and SnO2 nanopowders were used in lithium-ion cells for lithium storage. (c) 2005 Elsevier B.V. All rights reserved.