Role of thermoelectricity as a driving force in tribocharging

Triboelectricity has historically been challenging to pinpoint the origin of the thermodynamic driving force that underlies its omnipresence on any material interface. Here, we propose a ubiquitous triboelectric model based on thermoelectricity, which is generally applicable to solids, liquids, and even gas [1]. The driving force for tribocharing is quantified by the electrostatic potential drop at the interface caused by thermoelectric charge redistribution for frictional heat. This unprecedented quantification of triboelectricity leads to the first theoretical triboelectric series based on experimental thermodynamic parameters and theoretical Seebeck coefficients. Our ad hoc choice of Fermi energy from universal band alignment between semiconductors and water for theoretical Seebeck coefficients offers remarkable triboelectric series similar to experiments [2]. The water might be a feasible defect source in ambient friction determining the most likely Fermi energy. Our discoveries will lead not only to a deeper understanding of triboelectricity but also to a practical way of boosting the efficiency of triboelectric nanogenerators.n

[References]

1. E.-C. Shin, et al., Derivation of a Governing Rule in Triboelectric Charging and Series from Thermoelectricity, Phys. Rev. Res. 4, 023131 (2022). 

2. C. G. Van de Walle and J. Neugebauer, Universal Alignment of Hydrogen Levels in Semiconductors, Insulators and Solutions, Nature 423, 626 (2003).