The membrane materials of Ba_0.95Ce_0.8Y_0.2O_3–δF_0.10(BCYF_0.10) and Ce_0.8Y_0.2O_2–δ(YDC) ceramic powders were prepared by a sol–gel method. BCYF_0.10–YDC/BCYF_0.10–Ni double-layered asymmetric dense hollow fiber ceramic membrane was synthesized via co-spinning and co-sintering. The effects of spinning mixture composition and sintering temperature on the structure of hollow fiber membrane were investigated. The thickness of the dense layer, the interface between the two layers and the bending strength of the resultant hollow fiber membranes can be tuned by adjusting the ceramic powder loading in the inner and outer spinning solution. The thickness of the dense outer layer of the membrane is only 14.5 μm when the contents of ceramic powder in the inner and outer spinning solution are 65.7% and 44.4%, respectively. The two layers can be integrated well with the measured bending strength of 168.5 MPa. The prepared hollow fiber membranes were tested for hydrogen separation. At 900℃, when the feed gas (50% H₂+50% He) and the sweep gas (N₂) are controlled at 100 and 100 mL·min^–1, respectively, the hydrogen permeation flux of hollow fiber membrane is 0.54 mL·min^–1·cm^–2.

High conductivity two-dimensional (2D) materials have been proved to be potential electrode materials for flexible supercapacitors because of its outstanding chemical and physical properties. However, electrodes based on 2D materials always suffer from limited electrolyte-accessible surface due to the restacking of the 2D sheets, hindering the full utilization of their surface area. In this regard, an electrolyte-mediated method is used to integrate dense structure reduced graphene oxide/MXene (RGM)-electrolyte composite films. In such composite films, reduced graphene oxide (RGO) and MXene sheets are controllable assembly in compact layered structure with electrolyte filled between the layers. The electrolyte layer between RGO and MXene sheets forms continuous ion transport channels in the composite films. Therefore, the RGM-electrolyte composite films can be used directly as self-supporting electrodes for supercapacitors without additional conductive agents and binders. As a result, the composite films demonstrate enhanced volumetric specific capacity, improved volumetric energy density and higher power density compared with both pure RGO electrode and porous composite electrode prepared by traditional methods. Specifically, when the mass ratio of MXene is 30%, the electrode delivers a volumetric specific capacity of 454.9 F·cm⁻³ with a high energy density of 39.4 Wh·L⁻¹. More importantly, supercapacitors based on the composite films exhibit good flexibility electrochemical performance. The investigation provides a new approach to synthesize dense structure films based on 2D materials for application in high volumetric capacitance flexible supercapacitors.