Electrospun nano-fiber membrane

Nafion-112, and Nafion-212, use the thicker membrane Nafion-117 in DMFCs. The use of crosslinked PVA electrospun nano-fiber film supported Nafion composite membranes (Nafion/ PVA-fiber, thickness 50 pm) in DMFCs has been reported to exhibit a much better DMFC performance than Nafion-117 and Nafion/PVA blended PEMs [26-31]. Several researchers blended the Nafion PEMs with low methanol compatible PVA to reduce the methanol crossover in the PEMs [32-35]. However, these modified Nafion membranes had thicknesses greater than 175 pm, which were similar to (or higher than) that of the neat Nafion-117 membrane. Although there was a decrease in the methanol crossover from these Nafion/PVA blended membranes, the proton transfer resistance of these membranes increased, resulting in a lower DMFC performance. The advantage of applying the thin Nafion/PVA-fiber PEMs to the DMFCs is that the methanol crossover can be reduced without increasing the area specific resistance (i.e., Lla) because of low membrane thickness. Table 12.1 summarizes the thickness, proton conductivity, and Lja of the fiber reinforced Nafion composite membranes obtained from literature reports. The mechanical properties of the composite membranes reported in literature are also listed in Table 12.2. 

The PBI/PBI-PBz-f (thickness 75 pm) composite membrane containing 20 wt% of the PBI-PBz electrospun nano-fiber, of which 10 wt % was the PBz crosslinker, was doped with a phosphoric acid aqueous solution followed by MEA preparation to perform high-temperature fuel cell tests. The phosphoric acid doping level and proton conductivity, membrane mechanical properties, and fuel cell performance of this PBI/PBI-PBz-f composite are listed in Tables 12.3, 12.4, and 12.5, respectively. The data for neat PBI are given for comparison. The PBI/PBI-PBz-f composite membrane showed higher PAdop and a, higher mechanical strength and strain at break, and better fuel cell performance than the neat-PBI membrane. Compared to the hydrophobic porous PTFE film, the... 

Compared with Nafion/porous PTFE and Nalion/ electrospun nano-fiber composite membranes, there are few reports of PBl/porous PTFE and PBl/electrospun nano-fiber composite membrane for high temperature PEMFC appUcatiOTi. The PBl/porous PTFE composite membrane was shown to exhibit excellent mechanical strength and good durability, which allowed researchers to reduce the membrane thickness and thus reduce the area specific resistance and ultimately improve fuel cell performance. After the report of PBl/porous PTFE composite membrane, two... 

Cellulose is the most abundant biopolymer on earth. It can be used in different applications, namely in the form of fibers, and cellulose can be converted into numerous cellulose derivatives. Cellulose micro- and nanofibers have been the subject of intense research in the field of composites. Cellulose derivatives can show liquid crystalline chiral nematic phases, which can be used for the production of diverse composite systems. All-cellulosic composites based on liquid crystalline cellulosic matrices reinforced by cellulose micro- and nanofibers can show enhanced mechanical properties due to fiber orientation induced by the liquid crystalline matrix. Cellulose-based fibers electrospun from liquid crystalline phases can develop different structures, which are able to mimic the shape of plant tendrils on the nano- and microscale, opening new horizons for ceDulosic membrane applications. 

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