OPTIMIZATION OF ENERGY-STORAGE DENSITY IN CERAMIC CAPACITORS

A theoretical treatment, based on the Devonshire theory of ferroelectr ics, is presented to describe the storage of electrostatic energy in f erroelectric and paraelectric materials at very high field strengths. In all cases, optimal energy density is achieved by using compositions with Curie temperatures well below the operating temperature. The the ory is applied to barium-strontium titanate ceramics and optimal compo sitions are deduced for energy storage at given working fields. The th eory is supported by experimental data showing energy densities up to 8 J cm(-3) at 100 kV mm(-1).