Rare-earth (RE) doping can greatly enhance the voltage gradient of ZnO-based varistors, and their nonlinear coefficient, leakage current, energy absorption capability, through-current capability and residual voltage can also be improved to certain extent. In this review, the progress on RE-doped ZnO-based varistor materials in recent years was summarized. The mechanism of RE doping on the electrical performance of ZnO varistors was analyzed. The issues in exploring new ZnO-based varistor materials by RE doping were indicated, and the development trends in this area were proposed.
The authors would like to thank the financial support for this work from the National Natural Science Foundation of China (Grant Nos. 61274015, 11274052 and 51172030), the Transfer and Industrialization Project of Sci-Tech Achievement (Cooperation Project between University and Factory) from Beijing Municipal Commission of Education, and the Excellent Adviser Foundation in China University of Geosciences from the Fundamental Research Funds for the Central Universities.
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