Effect of different rare-earth elements on the dielectric and energy-storage characteristics of the (Ba0.4−xAxCa0.3Sr0.3)Nb2O6 bronze structure: [x = 0.0, 0.1, A = La3+, Nd3+ and Ho3+]
摘要
A significant challenge impeding the practical application of dielectric ceramics is the simultaneous achievement of high recoverable density of energy-storage (Wrec), efficiency (η), and break intensity (Eb) at high operating temperatures. The primary aim of the current study is to investigate how the ionic radii of different rare-earth ions [La3⁺ (1.38 Å), Nd3⁺ (1.27 Å), and Ho3⁺ (1.12 Å)] affect the disparity in grain size and resistivity at the grain boundaries of (Ba0.4Ca0.3Sr0.3) Nb2O6 (abbreviated BCSN) bronze structure ceramics. BCSN-based ceramics exhibit suppression of remnant polarization, a softly paired relaxor phase, and disruption of long-range ordering due to the disorder of foster cations and the enhancement of crystal lattice symmetry. Simultaneously, the reduction in grain size produced by the shorter ionic radius of doping-induced elevation of grain resistivity suppresses interfacial polarization, bolstering the breakdown of electric strength. The outcomes in the remaining performance of energy storing, eventually attaining a recoverable energy density equal to 9.20 J cm−3 and an 89.0% proficiency in (Ba0.3Ho0.1Ca0.3Sr0.3) Nb2O6 (BCSNH) ceramic, are ascribed to the lower radius (ionic) of Ho3+ compared to other doping. This research indicated that the smaller ionic radius and reduced grain size are effective factors for optimizing tetragonal tungsten bronze dielectric ceramic materials, resulting in significantly improved energy-storage performance.