Investigating the Composition of Iron Salts on the Performance of Microfluidic Fuel Cells

Abstract

Microfluidic fuel cells are a group of miniaturized fuel cells without membranes for operation. Their unique flow of the steams in a microchannel allows a parallel laminar flow without mixing with each other. We investigated the cell performance with different iron-based soluble salts as oxidants. The best performance was achieved by FeCl3 as the oxidant, achieving the highest power density of 192.71 mW cm–3 and the largest limiting current density of 883.33 mA cm–3 (normalized to the active electrode volume). And we optimized the performance of the FeCl3-based microfluidic fuel cell by adjusting the flow rates, HCl concentrations, and FeCl3 concentrations. The optimal flow rate was 20 mL h–1. Although the maximum power density of the cell with 4 M HCl and 0.5 M FeCl3 solution reached high values of 212.21 mW cm–3 and 250.42 mW cm–3, respectively, both cell performances were under mass transfer control at high current densities.