Polymer electrolyte fuel cells operating at elevated temperature and low relative humidity (RH) have been investigated by utilizing a polyoxometalate coupled graphene oxide-Nafion membrane. A phosphotungstic acid (PW) coupled graphene oxide-Nafion (Nafion/PW-mGO) membrane showed enhanced proton conductivity compared with pristine and recast Nafion membranes. The Nafion/PW-mGO hybrid membrane exhibited a maximum power density of 841 mW cm À2 , whereas the pristine Nafion membrane showed a power density of 210 mW cm À2 operated at 80 C under 20% RH. In comparison, our hybrid membrane showed a 4-fold higher maximum fuel cell power density when operated at 80 C under 20% RH, than that of a state-of-the-art pristine membrane (Nafion-212). The remarkably enhanced performance of the Nafion/PW-mGO composite membrane was mainly attributed to the reduction of ohmic resistance by the hygroscopic solid acids, which can retain water in their framework through hydrogen bonding with protons at elevated temperatures and facilitates proton transport through the membrane.

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A novel type of sandwiched separator for lithium-ion batteries has been developed by combining electrospinning and electrospraying techniques. This separator consists of three layers in which the top and bottom layers are prepared by electrospinning a poly(amic acid) ammonium salt (PAAS) solution and the middle layer is obtained by electrospraying a mixture of the PAAS solution and inorganic nanoparticles (SiO 2 or Al 2 O 3). Subsequently, the sandwiched separators are imidized at 250 C in a nitrogen atmosphere. The morphology, porosity, thermal stability, mechanical strength, wettability and electrochemical performance of sandwiched separators were examined and the results were compared with those of a commercial separator (SV718). The thermal properties of the sandwiched separators and SV718 were determined using a thermal gravimetric analyzer and a differential scanning calorimeter. The sandwiched separators had no melting peak, whereas SV718 had a melting peak at 139 C, demonstrating the higher thermal stability of sandwiched separators. The electrolyte contact angles of sandwiched separators were around 11.5 , which were significantly lower than that of SV718. Moreover, the porosity and electrolyte uptake of sandwiched separators were over 81% and 910%, respectively, while those values of SV718 were 43% and 121%, respectively. The higher porosity, electrolyte uptake, and wettability of the sandwiched separators resulted in the better their cycling performance and higher specific-discharge capabilities than SV718.