Ce2Zr2O7 nanotube in SPAEK block copolymer enhance ion selectivity and VRFB performance. The self-discharge time of SPAEK/Ce2Zr2O7 membrane was higher than pristine SPAEK and NRE-212 membrane.

Large-scale hydrogen production via electrochemical water splitting requires low-cost and efficient electrocatalysts that work well at high current densities with a low overpotential for the hydrogen evolution reaction (HER). Herein, we report the production of a NiCoSeP nanostructured electrocatalyst by a low-cost, one-step electrodeposition technique. The catalyst exhibits very high current densities at small overpotentials (100 mA cm–2 at 151 mV, 500 mA cm–2 at 286 mV, and 1000 mA cm–2 at 381 mV) in 1.0 M KOH electrolyte. Moreover, NiCoSeP shows excellent HER performance in an acidic medium with small overpotentials of 93 and 131 mV to deliver large current densities of 100 and 500 mA cm–2, respectively. The unique morphology of NiCoSeP, superhydrophilic, and superaerophobic properties could facilitate electrolyte diffusion and rapid delivery of the generated bubble, respectively. Our experimental data confirm that the advantages of the excellent HER activity and stability of NiCoSeP nanostructure originate from the high active surface area, bimetal double-anion effect, and enhanced mass transfer of reactants and hydrogen bubbles. This work may provide a promising way for rational design and simplify the synthesis process of practical electrocatalysts.

A proton exchange membrane fuel cell uses perfluorosulfonic acid polymers as a proton exchange membrane but exhibits poor performance and durability under dry operating condition. Herein, we develop a composite membrane by incorporating porous inorganic filler, Zr 2 Gd 2 O 7 , into a perfluorosulfonic acid, Nafion. Zr 2 Gd 2 O 7 nanorods (ZrGdNR) are synthesized using an electrospinning process and subsequently calcination under air atmosphere at 500 °C. The Nafion-ZrGdNR composite (Nafion-ZrGdNR) and NRE-212 membranes exhibit power densities of 858 and 695 mW cm −2 , respectively, at 0.6 V under 100% relative humidity at 80 °C. At 20% relative humidity, the maximum power density of the Nafion-ZrGdNR membrane (448 mW cm −2 ) is 3.8 times higher than that of a commercial NRE-212 membrane (119 mW cm −2 ), and moreover, the Nafion-ZrGdNR membrane exhibits a fluoride emission rate of 6.9 × 10 −5 ppm h −1 cm −2 , which is about 240 times lower that of than the NRE-212 membrane (1670 × 10 −5 ppm h −1 cm −2 ) for 120 h of open-circuit voltage testing. The composite membrane shows high proton conductivity, superior oxidative stability, and improved mechanical strength. The outstanding performance and remarkable durability of the Nafion-ZrGdNR membrane are due to its efficient water diffusion and stability against hydroxyl radical attack, resulting in low ohmic resistance and improved membrane degradation.

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A single-phase TiZrO 4 nanotube (TiZrO 4 NT)-incorporated Nafion composite membrane with ultrahigh ion selectivity is designed and fabricated for vanadium redox flow batteries (VFBs). A single cell of the VFB using the potential Nafion/ TiZrO 4 NT composite membrane shows high-capacity retention, low self-discharge rate, and high cycling efficiency. Furthermore, an excellent proton conductivity of 75.9 mS cm −1 at room temperature and 23-fold higher H + /VO 2+ selectivity (3.61 × 10 6 S min cm −3 ) are obtained for the Nafion/TiZrO 4 NT composite membrane compared with a state-of-the-art Nafion-212 membrane (55.4 mS cm −1 and 0.168 × 10 6 S min cm −3 ). Subsequently, a high VFB performance is achieved with 1.7-fold higher discharge capacity and impressive cycling Coulombic efficiency (CE, 99.8%), voltage efficiency (VE, 84.1%), and energy efficiency (EE, 83.9%) using the Nafion/TiZrO 4 NT composite membrane than those of the Nafion-212 membrane (CE, 89.9%; VE, 81.2%; and EE, 72.9%). Moreover, the low area resistance of the membrane, high-rate capability, excellent battery durability of 300 charge−discharge cycles, and high self-discharge time ensure the incorporation of the TiZrO 4 NT filler into the Nafion matrix and improve the selectivity of the fabricated Nafion/TiZrO 4 NT composite membrane. Consequently, the Nafion/TiZrO 4 NT composite membrane with ultrahigh ion-selectivity and superior battery performance is considered a potential candidate for high-performance VFBs.

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A zwitterionic SiO2 composite membrane (PFSA/Z-SiO2) was designed and fabricated for Zinc/Bromine flowless battery (ZBFLB) The composite membrane exhibits low Br2 crossover and high ionic conductivity. The optimized ZBFLB cell...