Superior energy density through tailored dopant strategies in multilayer ceramic capacitors

Research output: Contribution to journalArticlepeer-review

  • External authors:
  • Zhilun Lu
  • Weichao Bao
  • Jinglei Li
  • Linhao Li
  • Ali Mostaed
  • Huijing Yang
  • Hongfen Ji
  • Dejun Li
  • Antonio Feteira
  • Fangfang Xu
  • Derek C. Sinclair
  • Dawei Wang
  • Shi-Yu Liu
  • Ian M. Reaney


The Gerson–Marshall (1959) relationship predicts an increase in dielectric breakdown strength (BDS) and therefore, recoverable energy density (Wrec) with decreasing dielectric layer thickness. This relationship only operates however, if the total resistivity of the dielectric is sufficiently high and the electrical microstructure is homogeneous (no short circuit diffusion paths). BiFeO3–SrTiO3 (BF–ST) is a promising base for developing high energy density capacitors but Bi-rich compositions which have the highest polarisability per unit volume are ferroelectric rather than relaxor and are electrically too conductive. Here, we present a systematic strategy to optimise BDS and maximum polarisation via: (i) Nb-doping to increase resistivity by eliminating hole conduction and promoting electrical homogeneity and (ii) alloying with a third perovskite end-member, BiMg2/3Nb1/3O3 (BMN), to reduce long range polar coupling without decreasing the average ionic polarisability. These strategies result in an increase in BDS to give Wrec = 8.2 J cm−3 at 460 kV cm−1 for BF–ST–0.03Nb–0.1BMN ceramics, which when incorporated in a multilayer capacitor with dielectric layers of 8 μm thickness gives BDS > 1000 kV cm−1 and Wrec = 15.8 J cm−3.

Bibliographical metadata

Original languageEnglish
Pages (from-to)2938-2948
Number of pages11
JournalEnergy & Environmental Science
Issue number9
Publication statusPublished - 21 Aug 2020