posted on 2024-02-17, 17:03authored byJingmin Zhou, Gang Jing, Teng Zhao, Fengrui Tian, Xiaofei Xu, Shuangliang Zhao
The harvesting of salinity gradient energy through a
capacitive
double-layer expansion (CDLE) technique is directly associated with
ion adsorption and desorption in electrodes. Herein, we show that
energy extraction can be modulated by regulating ion adsorption/desorption
through water flow. The flow effects on the output energy, capacitance,
and energy density under practical conditions are systematically investigated
from a theoretical perspective, upon which the optimal operating condition
is identified for energy extraction. We demonstrate that the net charge
accumulation displays a negative correlation with the water flow velocity
and so does the surface charge density, and this causes a nontrivial
variation in the magnitude of output energy when water flows are introduced.
When high water flows are introduced in both the charging and discharging
processes, the energy extraction can be significantly reduced by 47.69–49.32%.
However, when a high flow is solely exerted in the discharging process,
the energy extraction can be enhanced by 12.94–14.49% even
at low operation voltages. This study not only offers a comprehensive
understanding of the microscopic mechanisms of surface-engineered
energy extraction with water flows but also provides a novel direction
for energy extraction enhancement.