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Two identical layered metal–organic frameworks (MOFs) (CoFRS and NiFRS) are constructed by using flexible 1,10‐bis(1,2,4‐triazol‐1‐yl)decane as pillars and 1,4‐benzenedicarboxylic acid as rigid linkers. The single‐crystal structure analysis indicates that the as‐synthesized MOFs possess fluctuant 2D networks with large interlayer lattices. Serving as active electrode elements in supercapacitors, both MOFs deliver excellent rate capabilities, high capacities, and longstanding endurances. Moreover, the new intermediates in two electrodes before and after long‐lifespan cycling are also examined, which cannot be identified as metal hydroxides in the peer reports. After assembled into battery‐supercapacitor (BatCap) hybrid devices, the NiFRS//activated carbon (AC) device displays better electrochemical results in terms of gravimetric capacitance and cycling performance than CoFRS//AC devices, and a higher energy‐density value of 28.7 Wh kg−1 compared to other peer references with MOFs‐based electrodes. Furthermore, the possible factors to support the distinct performances are discussed and analyzed.

Using the classical oscillator model, the optical dielectric functions for amorphous alumina (a-Al2O3) and gamma alumina (γ-Al2O3) thin films prepared by ion implantation and subsequent annealing of sapphire (α-Al2O3) substrates were determined for the first time from analysis of infrared reflection spectra. Two transverse optical modes at 422 and 721 cm−1 were obtained for the a-Al2O3 film while four modes at 357, 536, 744, and 807 cm−1 were identified for the γ-Al2O3 film. Also, the problems involving the analysis of modes with large damping are discussed.

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Recent progress in MOF materials for SCs with different spatial dimensions, such as 2D MOFs, including conductive MOFs and nanosheets, and 3D MOFs, categorized as single metallic and multiple metallic MOFs, are reviewed.

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The impedance of the junction between a solid or aqueous electrolyte and a metal electrode at which no charge transfer processes occur (blocking contacts) follows closely the constant phase angle form, Z = A(j omega)-n, over a wide frequency range, where A is a constant, and the frequency exponent n is typically in the range of 0.7 to 0.95. Several models have been proposed in which the magnitude of the frequency exponent n is related by a simple expression to the fractal dimension d of the rough electrode surface. But experiments with aqueous H2SO4 and roughened platinum and silicon electrodes show that there is no simple relationship, if any at all, between n and d when d is determined from the analysis of one dimensional surface profiles. Moreover, n is not a simple function of the average roughness of the electrode. In order to gain some insight into the effect of electrode topography and the interface impedance, a model for the response of the interface to a constant voltage pulse was constructed. This model is based on the idea that, following a pulse, locally concentrated regions of ions accumulate rapidly at the tips of large protrusions on the electrode surface which screens deeper regions of the electrode from the field driven flux of mobile ions. After this rapid charging, ions are able to reach the deeper, screened regions of the electrode by diffusion, and it is this diffusive process that gives rise to the observed t1-n dependence of the charge collected. Computer simulations, similar to the diffusion limited aggregation model, using measured profiles as fixed (non-growing) clusters, gave exponents n in good agreement with experiment.

Different amount of carbon and nitrogen, for MOF-derived nitrogen-doped carbon/Mn3O4 composites, can result in the discrepancies of synergistic effect which plays an important role in final electrochemical performance.