WO(3) nanorods are uniformly coated with SnO(2) nanoparticles via a facile wet-chemical route. The reversible capacity of SnO(2)/WO(3) core-shell nanorods is 845.9 mA h g(-1), higher than that of bare WO(3) nanorods, SnO(2) nanostructures, and traditional theoretical results. Such behavior can be attributed to a novel mechanism by which nanostructured metallic tungsten makes extra Li(2)O (from SnO(2)) reversibly convert to Li(+). This mechanism is confirmed by x-ray diffraction results. Our results open a way for enhancing the reversible capacity of alloy-type metal oxide anode materials.