DC Aging Mechanism of Co2O3-Doped ZnO Varistors

Lowered power loss and asymmetrically electrical parameters are reported in the DC aging of Co2O3-doped ZnO varistors in this paper. Based on the frequency domain dielectric responses of the pristine and degraded samples, the present study explores the roles of point defects in the aging process via...

Full description

Saved in:
Bibliographic Details
Published inEnergies (Basel) Vol. 14; no. 13; p. 4011
Main Authors Zhao, Xia, Shen, Haibin, Guo, Men, He, Ziming, Li, Yupeng, Wen, Ran
Format Journal Article
LanguageEnglish
Published Basel MDPI AG 01.07.2021
Subjects
Aging
Bismuth oxides
Bismuth trioxide
Cobalt oxides
Crystal defects
DC aging
Dielectric properties
Dielectric relaxation
double Schottky barrier
Electric fields
Electric power loss
Grain boundaries
Leakage current
Oxygen ions
Parameters
Point defects
Polyvinyl alcohol
Raw materials
Spectrum analysis
Zinc oxide
ZnO varistors
Online AccessGet full text

Cover

More Information
Summary:Lowered power loss and asymmetrically electrical parameters are reported in the DC aging of Co2O3-doped ZnO varistors in this paper. Based on the frequency domain dielectric responses of the pristine and degraded samples, the present study explores the roles of point defects in the aging process via dielectric relaxations and their parameters. It is found that breakdown field increased more in the positive direction than the negative direction. Nonlinearity increased in the positive direction, whereas it decreased in the negative direction, and leakage current density increased more in the negative direction than the positive direction. Given the lowest migration energy of Zinc interstitial (Zni, 0.57 eV) and high oxygen ion conductivity in Bi2O3-rich phase, it is speculated that Zni and adsorbed oxygen (Oad) migrate under DC bias, and then change the defect structure and the double Schottky barrier (DSB) at grain boundaries. As a result, the forward-biased barrier height gradually decreases more than the reverse-biased one.
ISSN:1996-1073
1996-1073
DOI:10.3390/en14134011