How do the non-linear I–V curves of ZnO-based adaptive composites behave with electrodes placed on the opposite sides with a series of horizontal distances?

Recently, ZnO-based composites have been widely applied in the field of electric power. To meet the diverse application requirements, it is necessary to figure out the I–V characteristics of ZnO composites whose high-voltage and ground-voltage electrodes are arranged on the opposite sides with a certain horizontal distance. 30 vol%, 40 vol% and 50 vol% ZnO-based silicone rubber composites were prepared. The horizontal distance between their electrodes was set as 50, 100, 500 μm, 1 and 2 mm, respectively. Results showed that with the increase of ZnO fillers volume fraction under a fixed horizontal distance of 100 μm, from 30 vol% to 50 vol%, the I–V curves shifted left, the leakage current increased and the switching voltage decreased. When the horizontal distance between electrodes increased from 50 μm to 1 mm under a fixed doping concentration of 40%, the I–V curves shifted to the right, the leakage current dropped and the switching voltage rose. The mathematical and physical models were established to explain the results. This work provides a referential significance for the practical application of ZnO composites, such as 5G folding mobile phones and power electronic modules.