Fig. 3: Temperature effect on the CE between the DI water and the solids.

The decay of CE charges (induced by contacting with the DI water at room temperature) on a MgO, b Si₃N₄, c Ta₂O₅, d HfO₂, e Al₂O₃, and f AlN surfaces at 433 K, and the amount of the electron transfer and the ion transfer in the CE between the DI water and different insulators. g The relation between the electron transfer to the ion transfer ratio and the DI water contact angle (WCA) of the materials. h The schematic of WCA effects on the ion transfer and electron transfer in liquid–solid CE. γ_L, γ_S, and γ_L−S denote the liquid–gas interfacial tension, solid–gas interfacial tension and liquid–solid interfacial tension, respectively. (Error bar are defined as s. d.).