Interfacial origin of enhanced energy density in SrTiO3-based nanocomposite films

SrTiO 3 -based films doped with different Al-precursors were prepared by sol-gel methods and the dielectric strengths and leakage currents of the materials were investigated. The best performance was found in SrTiO 3 films doped with Al 2 O 3 nanoparticles (nano-Al 2 O 3 ). When 5   mol% of nano-Al 2 O 3 was added to SrTiO 3 films with Al electrodes, the dielectric strength was enhanced to 506.9   MV/m compared with a value of 233.5   MV/m for SrTiO 3 films. The energy density of the 5   mol% nano-Al 2 O 3 doped SrTiO 3 films was 19.3   J/cm 3 , which was also far higher than that of the SrTiO 3 films (3.2   J/cm 3 ). These results were attributed to interfacial anodic oxidation reactions, which were experimentally confirmed by cross-sectional transmission electron microscope studies and theoretically modelled based on Faraday's laws . The films with added nano-Al 2 O 3 featured many conducting paths at the interfaces between the host phase and the guest nano-Al 2 O 3 , which promoted ion transport and contributed to the strong anodic oxidation reaction capability of the 5   mol% nano-Al 2 O 3 doped SrTiO 3 films.