Influence factors of thermal driven ion transport in nano-channel for thermoelectricity application

Abstract

Many attentions have been paid on discussing isothermal transport in electrolyte-filled wall-charged nano-pores or nano-channels, while the non-isothermal transport has been scarcely considered before. In this work, a calculation model based on Poisson–Nernst–Planck equation is established to describe the thermal driven ion transport in nano-channels. The effects of different influence factors on the ion transport is carefully studied, including effects of the temperature difference across nano-channel, the ion concentration, the half-width of nano-channel, and the length of nano-channel. Results turn out that: performances of nano-channel batteries can be classified and simplified by using characteristic parameters and ion concentrations; the ion concentration of about 1 mol•m−3 and the nano-channel half width (h) of about 1 nm is optimal for thermoelectricity applications, and if the optimal nano-channel length of about 85 h and the optimal temperature difference of about 85 K are further applied, the thermally induced power of the system can be maximized. This study is expected to supply some information for designing a nano-channels system with high thermos-electric energy conversion efficiencies.