BaTiO3/Bi2O3-B2O3-SiO2 Glass Core-Shell Nanocomposites for Energy Storage Applications

X. Su, B.C. Riggs, M. Tomozawa, D.B. Chrisey
Rensselaer Polytechnic Institute, US

Keywords: core-shell, nanocomposites, grain size, energy storage

Summary:

The dielectric and ferroelectric properties of barium titanate have exhibited a strong dependence on grain size. Both the linear polarization response and high dielectric breakdown strength of nanocrystalline barium titanate make it attractive for high energy storage capacitors applications. In order to obtain dense bulk nanocrystalline BaTiO3, glass addition is necessary to fill the pores of barium titanate to promote densification. This work applies a modified sol-gel process to fabricate barium titanate/low melting glass Bi2O3-B2O3-SiO2 core-shell nanopowders. Preliminary results showed that this coating layer can not only promote densification up to 99% relative density but also prevent the grain growth of barium titanate during the sintering process. This is the first observation of highly densified (≥99% T. D.) barium titanate/glass composites with nano-grain size maintained after sintering. This nanocrystalline barium titanate glass composites exhibited relative permittivity of ~560 at room temperature and dielectric breakdown strength of ~390 kV/cm with 300 micron sample thickness which gives an energy storage density of 3.7 J/cm3 for a bulk sample.