Structure-improved current collector for performance enhancement of electrolyte membrane dehumidifiers: 3D simulations and in-situ measurements

Abstract

Electro-dehumidification based on proton exchange membrane (PEM) is promising owing to its compact assembly and convenient operation. By numerically improving the effects of current collectors’ structure on the operation performance (moisture removal rate, current/temperature/humidity distribution and energy utilization rate), this research achieved a significant dehumidification enhancement (more than 40%) for electrolyte membrane dehumidifiers. 3D Multiphysics simulation and in-situ verification measurements were conducted. Compared with the original collectors, the dehumidification rate can be enhanced by 35% with the “口” collectors, and by more than 40% with “X”, “#” and “▪” collectors. The best performance occurred with the anode collector of “▪” structure (opening area: 9 × 10-4 m2), which the rate increased by 46%. The improvement effects were mainly due to the improvement of potential distribution (especially on the anode side) and the concentration of the reactant (water vapor) reaching the catalyst interface. Compared with the “口” type, the current density uniformity of membrane dehumidifier with the “▪” collector increased from 0.0033 to 0.032. The temperature and moisture distribution were also more uniform. The opening structure of anode collector resulted in a more significant effect than the opening area. Therefore, the system energy utilization rate and COP (coefficient of performance) can be doubled, up to 3.48 × 10−2 g·J−1·m−2 and 0.26, respectively. This research provides a theoretical basis and practical direction for improving current collectors of PEM dehumidifiers.