Fluidity and penetration efficiency of Zn particles on the electrochemical reactions of Zn-air fuel cells

摘要

Zinc-air fuel cells (ZAFCs) have great potential as next-generation green energy sources. However, a practical application remains a challenge, because to achieve continuity and automation the operation of ZAFCs includes manipulation of the electrolyte and Zn fuel, for which the control of liquid-solid interface is difficult. Therefore, a fluid-circulation system has been developed for a ZAFC in this study. A flowing electrolyte is used to feed the Zn particles into the cell. Moreover, the operation parameters are adjusted to obtain the best cell performance, and a Ni-filter current collection grid (CCG) has been incorporated. The experimental results show that the optimal area for the Ni-filter CCG box is 300 cm(2), and 0.15 mm Zn particles are optimal for facilitating cell efficiency. The flow rate requires appropriate control to allow Zn particles to complete their reaction. A flow rate of 65 mL/min was found to be optimal. After optimization of the parameters, a single cell can produce a maximum power of 19 W, under a continuous feed of 400 mA/cm(2), with a corresponding peak current density of 500 mA/cm(2). It is capable of continuous discharge for up to 300 min when the voltage is maintained above 0.8 V, thus verifying the potential and feasibility of the proposed design.