The separation of H2/CH4 mixtures is very common in the natural gas and petrochemical industries. There are some higher C2–C4 hydrocarbons and water vapor that are used as impurity gases. Si-CHA zeolite membranes display a high H2 permeance of 1.44 × 10–6 mol/(m2 s Pa) (permeability of 10800 barrers) and H2/CH4 selectivity of 85 for an equimolar H2/CH4 mixture at 298 K and 0.2 MPa pressure drop. A third gas decreased H2 permeance and H2/CH4 selectivity of the membrane. Hydrogen permeance was reduced in an order similar to the adsorption amount in zeolite: H2O > C3H8 > n-butane > ethane. The effects of temperature, pressure, and feed concentration were studied on separation performances of the membrane in the binary and ternary mixtures. A simple model was built up to predict the reduction of permeance and selectivity when multi impurities were contained, and the predicted value agreed well with the tested one. A stable performance was obtained within several hours in all the tests. The separation performance of the membrane was recovered to the original level when the impurity gas was removed.

Na4MnV(PO4)3/C (NMVP) has been considered an attractive cathode for sodium‐ion batteries with higher working voltage and lower cost than Na3V2(PO4)3/C. However, the poor intrinsic electronic conductivity and Jahn–Teller distortion caused by Mn3+ inhibit its practical application. In this work, the remarkable effects of Zr‐substitution on prompting electronic and Na‐ion conductivity and also structural stabilization are reported. The optimized Na3.9Mn0.95Zr0.05V(PO4)3/C sample shows ultrafast charge‐discharge capability with discharge capacities of 108.8, 103.1, 99.1, and 88.0 mAh g−1 at 0.2, 1, 20, and 50 C, respectively, which is the best result for cation substituted NMVP samples reported so far. This sample also shows excellent cycling stability with a capacity retention of 81.2% at 1 C after 500 cycles. XRD analyses confirm the introduction of Zr into the lattice structure which expands the lattice volume and facilitates the Na+ diffusion. First‐principle calculation indicates that Zr modification reduces the band gap energy and leads to increased electronic conductivity. In situ XRD analyses confirm the same structure evolution mechanism of the Zr‐modified sample as pristine NMVP, however the strong ZrO bond obviously stabilizes the structure framework that ensures long‐term cycling stability.

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