Crystallization kinetics, breakdown strength, and energy-storage properties in niobate-based glass-ceramics

Abstract In this work, (100- x )(0.12 SrO-0.3 Na 2 O-0.1 Nb 2 O 5 )- x SiO 2 ( x  = 30, 35, 40, 45, 50 mol%) glass-ceramics were prepared by using the meth-quenching-controlled crystallization method. Phase evolution, Crystallization mechanism, dielectric properties, dielectric breakdown strength (DBS), and energy-storage performances were comprehensively studied by varying SiO 2 content. DSC studies revealed simultaneous occurrence of surface and internal crystallization mechanism in the glass-ceramics. XRD results showed three tungsten bronze structure SrNb 2 O 6 , Sr 6 Nb 10 O 30 , NaSr 2 Nb 5 O 15 phases and perovskite structure NaNbO 3 phase, which was quantified by the Reietveld refinement. It was found that dielectric constant and theoretical energy-storage density increased firstly and then decreased with the increase of the SiO 2 contents. For x  = 35 mol%, the theoretical energy-storage density reaches the maximal value of 15.3 J/cm 3 due to the highest dielectric constant of 124 and DBS of 1669 kV/cm. And the highest DBS is related to the uniform and dense microstructure for x  = 35 mol%. For practical applications in pulsed RLC circuit, the discharged efficiency increases from 74.2% to 91.5% with the increase of the SiO 2 contents.