Membrane Applications in Electrochemical Devices for Energy Storage and Conversion

5 MEMBRANE APPLICATIONS IN ELECTROCHEMICAL DEVICES FOR ENERGY STORAGE AND CONVERSION 

PFSA membranes have excellent chemical inertness and mechanical integrity in a corrosive and oxidative environment, and their superior properties allowed for broad application in electrochemical devices and other fields such as superacid catalysis, gas drying or humidification, sensors, and metal-ion recovery. Here, we refer their important applications in electrochemical devices for energy storage and conversion including PEMFC, chlor-alkali production, water electrolysis, vanadium redox flow batteries, lithium-ion batteries (LIBs), and solar cells. 

The membrane must be resistant to the harsh oxidative environment at the anode as well as the reducing environment at the cathode. In addition, to achieve high efficiency, the membrane must possess the following desirable properties high proton conductivity and zero electronic conductivity, adequate mechanical strength and stability, chemical and electrochemical stability under operating conditions, extremely low fuel or oxygen crossover to maximize coulombic efficiency, and production costs compatible with intended application.  

PFSA membrane is by far the most studied proton electrolyte for PEMFC. There are three advantages to the use of PFSA membranes in PEMFCs. First, due to PTEE-based backbone, PFSA membranes are relatively strong and stable in both oxidative and reductive environments. In fact, durability of 60,000 h has been reported. Second, the proton conductivity achieved in PFSA manbrane can be as high as 0.13 S/cm at 75°C and 100% relative humidityA ceU resistance is as low as 0.05 cm for a 100 pm thick membrane with voltage loss of only 50 mV at 1 A/cm. Third, PFSA has relatively good mechanical properties. For Nafion 

FIGURE 2.12 Schematic of hydrogen and methanol fueled polymer electrolyte membrane fuel cell (PEMFC) with a proton-conducting membrane. 

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