Rapid conduction of NiO-based ceramic resistors: the competitive relationship between electron–hole exchange and screening effect

NiO-based ceramic resistors doped with Li⁺, Na⁺, and K⁺ were prepared using the traditional solid-state method. The effects of microstructure and electrical properties of NiO-based ceramic resistors doped with alkali metal ions of varying ionic radii were investigated. XPS and Raman spectra indicate that doping with alkali metal ions promotes the valence state change of nickel ions from Ni²⁺ to Ni³⁺, facilitating charge transfer. The acceleration of charge transfer is beneficial for decreasing resistivity, improving single-pulse discharge rate, and optimizing I–V characteristics. Additionally, the increasing difference in radius between the dopant ions and Ni²⁺ ions enhances the screening effect, which increasingly hinders the charge transfer process. The NiO-based ceramic resistor doped with Li⁺ ions exhibited the best comprehensive electrochemical performance with a nonlinear coefficient α of 1.04, a resistivity ρ value of 4.83 Ω·cm, a shortest single-pulse discharge time t_0.9 of 94 ns, and a resistance temperature coefficient α_T value of − 1.25 × 10^–2 °C⁻¹.