Defect dipole induces nonlinear performance in ZnO varistor ceramics exhibiting superior high voltage gradient

Due to their excellent electrical potential stranglehold capability to over-voltage, ZnO-Bi 2 O 3 based varistor ceramics are extensively utilized in surge arresters. Unfortunately, Bi 2 O 3 has high volatility at high-temperature sintering, and ZnO-Bi 2 O 3 based varistor ceramics has a complex formulation that is difficult to control. Recently, the approach of constructing defect dipoles through defect engineering have emerged as an effective strategy to enhance the performance of electroceramics. In this paper, we introduce Fe 3+ as donor and Li  +  as acceptor to replace Zn 2+ for constructed defective dipole pairs in the ZnO lattice. The substitution enables induced the nonlinear conductivity properties in ZnO at lower doping levels. Meanwhile, the result as designed (Fe 0.5 Li 0.5 ) x Zn 1- x O 2 varistor ceramics ( x  = 20 mol%) exhibit a breakdown voltage gradient E b of 1422.09 V/mm. The research provides a new perspective for developing high-performance bismuth-free ZnO-based varistor ceramics.