Surface charge and thermal dependence of energy conversion in nanochannels

Micro/nanofluidics based energy conversion has drawn much attention in recent years. In this work, an ion transport model driven by pressure and temperature gradient is proposed to investigate the energy conversion characteristic in nanochannels. The results illustrate that the power generation performance under the different electrical boundary conditions exhibit a significant deviation. The output power is weakened at low and high solution concentrations/pH values, the maximum output power is corresponding to 5% and 50% deviation, respectively. And it is improved with the increasing temperature and pressure gradient due to the significant enhanced current. Especially, the maximum output power of 720 nW/m is obtained when the temperature difference is 20 °C and pressure gradient is 0.025 MPa/μm, which is corresponding to 21% enhancement than isothermal condition. Besides, we found that the Soret effect plays an important role on ion transport and the viscous dissipation effect can be neglected. The obtained results offer the valuable information for the performance optimization in micro/nanofluidic based energy devices.