Improved Energy Storage Properties of Fine‐Crystalline BaTiO 3 Ceramics by Coating Powders with Al 2 O 3 and SiO 2

The multilayer structure of capacitor demands for fine grain size of dielectric ceramics in devices, because the thinner layer which needs ceramics with fine grain size is helpful in enlarging the capacitance. In this paper, the aqueous chemical coating method was utilized to modify the BaTiO 3 particles. The fine‐crystalline BaTiO 3 ceramics with an average grain size below 200 nm without abnormal grain growth by co‐coating Al 2 O 3 and SiO 2 has been prepared. The phase composition, microstructures of coated particles and ceramics, and dielectric properties were investigated. For samples containing 3 wt% of Al 2 O 3 and 1 wt% of SiO 2 , the energy storage density is 0.725 J/cm 3 and the efficiency of the ceramic samples can keep above 80%. The breakdown strength was improved to about 190 kV/cm.