The research on supercapacitors (SCs) is one of the hot topics in the field of energy storage, and the intrinsic ageing mechanism of SCs is significant from both the economic and the scientific point of view. In this paper, the negative effects of decay of the key structural components on ageing of SCs were investigated by factorial design and analysis of variance (ANOVA). The ANOVA results showed that the degree of the negative influence on ageing of SCs could be ranked in descending order as anode > separator > cathode. The ageing would be accelerated due to the interaction between the electrode and separator, especially at a high charge−discharge current density. Further, the intrinsic chemical ageing mechanism of SCs was revealed by the morphology, microstructure, and chemical composition analyses of the fresh and aged key components (the electrode carbon materials, current collectors, and separators) with scanning electron microscopy (SEM), Brunauer−Emmett−Teller (BET), X-ray photoelectron spectra (XPS), time-of-flight secondary ion mass spectrometry (TOF-SIMS), wide-angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), Fourier transform infrared (FTIR), etc. Moreover, the minimum pore width of electrode carbon materials suitable for electrolyte ion diffusion was obtained by density functional theory (DFT) calculations, which corroborated the assumption that the pore structure deterioration was one of the direct causes of capacitance loss for aged SCs. Generally, the ageing mechanism of key components of SCs could be a reference to develop advanced electrode materials and separators for SCs.

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Activated carbon is widely used in many fields because of its well-developed pore structure. Especially in hemoperfusion, activated carbon beads derived from macroporous resin spheres are the predominant adsorbents in hemoditoxifiers. In comparison, biomass-activated carbon attracts more extensive attention on account of its renewability and environmental protection. In this study, a lotus root-type monolithic-activated carbon with a hierarchical pore structure was made from rice husks by the injection molding process followed by carbonization and activation. The straight square channels with the side length of about 1.3 mm were designable, and these channels with adjustable lengths were favorable for the fluid flow during blood purification compared with the tightly packed carbon beads in commercialized hemoditoxifiers. Complementally, the hierarchical nano-sized pores in the walls of the big channels would contribute much to the adsorption capacity for the monolith. Specifically, the adsorption of vitamin B12, a representative of middle molecular toxins in human blood, was about 3.7 mg g–1, which was acquired by simulated in vitro hemoperfusion tests and this demonstrated the promising application of the lotus root-type biomass-activated carbon in hemoperfusion.

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Computation Fluid Dynamics (CFD) has been employed to calculate the pressure, flow distributions and leakage of brush seal by using Reynolds-Averaged-Navier-Stokes (RANS) method and two-dimensional axisymmetric anisotropic porous medium model. The leakage in brush seal with radial clearance has a marked increase compared with contact brush seal. The leakages of brush seal with different radial clearances have been investigated comparing contact brush seal. A type ofretaining ring structure has been employedto reduce the leakage on radial clearance condition. Also the disturbance effect of retaining ring on bristle pack has been studied.