09-09-2017, 09:56 AM
The effect of flow and flow anode architectures as well as operating conditions such as different fuel flow rates and LFFC performance concentrations were investigated. Formic acid at concentrations of 0.5 M and 1 M was exploited in a solution of 0.5 M sulfuric acid as support electrolyte at variable flow rates of 20, 50, 100 and 200 μl / min. Due to improved mass transport to catalytic active sites, the continuous flow anode showed improved maximum power density and single pass fuel utilization compared to the planar flow anode. Maximum power densities of 26.5 mW / cm 2 and 19.4 mW / cm 2 were obtained for the cells with flow and flow anodes, respectively, over 200 μl / min of 1 M formic acid. In addition, the chronoamperometry experiment at a flow rate of 100 μl / min at 0.5 M and 1 M fuel concentrations revealed mean current densities of 34.2 mA / cm 2 and 52.3 mA / cm 2 with an average fuel utilization of 16.3% and 21.4% through design. The upflow design had the corresponding values of 25.1 mA / cm2 and 35.5 mA / cm2 with a fuel utilization of 11.1% and 15.7% for the same fuel and flow rates.
The membraneless LFFCs benefit from the lamination of multiple currents in a microchannel. The lack of convection mixing leads to a well-defined liquid-liquid interface. Normally, the anode and the cathode are located on both sides of the interface. The liquid-liquid interface is considered as a virtual membrane and the ions can travel through the channel to reach the other side and complete the ionic conduction. The advantage of the LFFC membrane is the lack of a physical membrane and the problems related to the conditioning of the membrane can be eliminated or become less important. Based on electrode architectures, membraneless LFFCs in the literature can be classified into three main types: flow design with planar electrodes, flow design with three-dimensional porous electrodes and membraneless LFFC with air-breathing cathode. Since this paper focuses on reviewing the design considerations of LFFC membraneless, a concept map is provided for understanding cross-problems.
The membraneless LFFCs benefit from the lamination of multiple currents in a microchannel. The lack of convection mixing leads to a well-defined liquid-liquid interface. Normally, the anode and the cathode are located on both sides of the interface. The liquid-liquid interface is considered as a virtual membrane and the ions can travel through the channel to reach the other side and complete the ionic conduction. The advantage of the LFFC membrane is the lack of a physical membrane and the problems related to the conditioning of the membrane can be eliminated or become less important. Based on electrode architectures, membraneless LFFCs in the literature can be classified into three main types: flow design with planar electrodes, flow design with three-dimensional porous electrodes and membraneless LFFC with air-breathing cathode. Since this paper focuses on reviewing the design considerations of LFFC membraneless, a concept map is provided for understanding cross-problems.