Relative humidity effects fuel cell performance

Chalkova, E., M.V. Fedkin, D.J. Wesolowski et al. 2005. Effect of Ti02 surface properties on performance of Nafion-based composite membranes in high temperature and low relative humidity PEM fuel cells. Journal of Electrochemical Society 152 A1742-A1747. 

One of the frequently advertised advantages of the phosphoric acid imbibed polybenzimidazole systems is their zero water drag coefficient and their possibihty to operate with dry hydrogen and oxygen. However, a vast literature has been devoted to the study of the proton conduction and the effect of relative humidity on the conductivity of the PBl-phosphoric acid system. The promoting effect and the physicochemical interactions of water vapors with the polymer electrolyte and on the fuel cell performance have been explicitly shown for the PBl/PPy(50)coPSF 50/50 polymer blend imbibed with phosphoric acid under fuel cell conditions. ... 

Zhang J, Tang Y, Song C, Xia Z, Wang H, Zhang J, et al. Effect of relative humidity on PEM fuel cell performance at elevated temperature. Forthcoming 2008. 

Chippar P, Kang K, Lim YD et al (2014) Effects of inlet relative humidity (RH) on the performance of a high temperature-proton exchange mcanbrane fuel cell (HT-PEMFC). Int J Hydrogen Energy 39 2767-2775... 

The effects of relative humidity on the MEA performance are widely studied and the direct relationship between humidity increase and carbon corrosion are well noted in previous literature. The inevitability of humidity and water moisture in a fuel cell prompts for alternative operating methods or alternative catalyst supports which are more stable in a wide variety of PEMFC atmospheres. 

In general, fuel cell performance can be affected by several operating conditions, such as temperature, pressure, and relative humidity (RH). We will discuss the effects of RH and pressure in Chapters 8 and 9, respectively. In this chapter, only the temperature effects on the performance of PEM fuel cells wUl be discussed in detaU. 

As briefly mentioned in Section 4.3.S.2, Atiyeh et al. [152] performed water balance measurements and calculations to determine the effect of using DLs with MPLs (on either or both cathode and anode sides). In their fuel cell test station, water collection systems were added in order to be able to collect and measure accurately the water leaving both anode and cathode sides of the fuel cell. Based on the operating conditions (e.g., pressures, temperatures, relative humidities, etc.) and the total amount of water accumulated at the outlets of the test station, water balance calculations were performed fo defermine the net water drag coefficient. Janssen and Overvelde [171] used this method to observe how different operating conditions and fuel cell maferials affected... 

Figure 6.7. Polarization curves for different concentrations of NO . Cell temperature 60°C, H2/air (1.2/3.3) relative humidity H2 95% and air 0% backpressure 1.5 atm [49], (Reprinted from Electrochimica Acta, 51(19), Yang Daijun, Ma Jianxin, Xu Lin, Wu Minzhong and Wang Haijiang, The effect of nitrogen oxides in air on the performance of proton exchange membrane fuel cell, 4039-44, 2006, with permission from Elsevier.)...

---