Ag and SnO2 nanopowders were synthesized by reverse-micelle method. The reverse micelles were prepared to form tiny aqueous droplets dispersed in oil-based solvents. Two reverse micelles containing metallic salts and reductive agents were rigorously mixed to form nanoparticles inside aqueous droplets by a reductive reaction. The spherical powders of 20~50 nm were formed during the process. The resulting Ag and SnO2 nanopowders were examined as the anode electrode for lithium-ion cells. The reversible discharge capacity of the Ag and SnO2 nanopowders after 25 cycles were 315 and 380 mAh/g, respectively.