Novel BaTiO3-Based, Ag/Pd-Compatible Lead-Free Relaxors with Superior Energy Storage Performance

Ceramic dielectrics are reported with superior energy storage performance for applications, such as power electronics in electrical vehicles. A recoverable energy density ( W rec ) of ∼4.55 J cm -3 with η ∼ 90% is achieved in lead-free relaxor BaTiO 3 -0.06Bi 2/3 (Mg 1/3 Nb 2/3 )O 3 ceramics at ∼520 kV cm -1 . These ceramics may be co-fired with Ag/Pd, which constitutes a major step forward toward their potential use in the fabrication of commercial multilayer ceramic capacitors. Compared to stoichiometric Bi(Mg 2/3 Nb 1/3 )O 3 -doped BaTiO 3 (BT), A-site deficient Bi 2/3 (Mg 1/3 Nb 2/3 )O 3 reduces the electrical heterogeneity of BT. Bulk conductivity differs from the grain boundary only by 1 order of magnitude which, coupled with a smaller volume fraction of conducting cores due to enhanced diffusion of the dopant via A-site vacancies in the A-site sublattice, results in higher breakdown strength under an electric field. This strategy can be employed to develop new dielectrics with improved energy storage performance.