Titanium dioxide (TiO 2 ) is usually introduced into dielectric layer of aluminum electrolytic capacitor to enhance capacitance performance via forming Al 2 O 3 –TiO 2 composite film. However, there is a big obstacle caused by high crystallization temperature of TiO 2 to capacitance enhancement. In present work, a facile route was proposed to synthesize crystalline TiO 2 with the size of 3–10nm at room temperature using lactic acid (LA) and acetylacetone (Acac) as double chelators. After being introduced into the surface of etched aluminum foils as dielectric layer, TiO 2 boosted the specific capacitance by about 24% compared to that without TiO 2 , and about 11% compared to that with TiO 2 using lactic acid as only chelator.