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[en] Graphical abstract: Solid–gas thermochemical multilevel sorption thermal battery for cascaded thermal energy storage. - Highlights: • A novel solid–gas thermochemical multilevel sorption thermal battery for energy storage. • Cascaded solar heat storage using thermochemical multilevel sorption thermal battery. • Performance of the thermochemical multilevel sorption thermal battery is analyzed. • The proposed method has high energy density and broad working temperature range. • Energy density of the proposed method is sensitive to chemical global conversion. - Abstract: An innovative solid–gas thermochemical multilevel sorption thermal battery is developed for cascaded solar thermal energy storage to enhance the versatility and working reliability of solar heat storage system by widening the working temperature range. Solar thermal energy can be stored in the form of bond energy of sorption potential at different cascaded temperatures resulting from solid–gas thermochemical multilevel sorption processes. The operating principle and working performance of the thermochemical multilevel sorption thermal battery for energy storage is described and analyzed. Thermodynamic analysis showed that the proposed thermochemical multilevel sorption thermal battery has the potential capacity for meeting the challenge of solar heat storage during the random variation of low and high solar insolation with time by using cascaded thermal energy storage technology. An energy density higher than 1200 kJ/kg of reactant can be attained from the advanced energy storage system. The promising method can enhance the versatility and working reliability of solar heat storage due to its distinct advantages of high energy density and a wide range of solar collection temperature when compared with conventional heat storage methods. It has potential applications for energy management of renewable energy utilization and waste heat recovery in large-scale industrial processes.
[en] (0 0 0 1) α-Al2O3 single crystals (sapphire) were implanted with Zn ions of 60 keV at a fluence of 1 x 1017 ions/cm2. Transmission electron microscopy and optical absorption spectroscopy studies show the formation of ZnO nanoparticles in the sapphire substrate after the implanted sample was annealed at 700 oC in oxygen ambient. The photoluminescence spectrum of the annealed sample indicates the formation of ZnO nanoparticles with perfect lattice structure. The selected-area electron diffraction pattern proves that the ZnO nanoparticles have the (0 0 0 2) orientation which follows the orientation of Al2O3 substrate. The result shows that the crystallographic orientation of nanoparticles obtained through ion implantation is defined by the substrate.
[en] TiO2 thin films fabricated by direct-current (DC) reactive magnetron sputtering were implanted with Ag ions at 30 kV to fluences of 1 × 1016, 3 × 1016 and 5 × 1016 ions/cm2, and subsequently annealed at 500 °C for 2 h under Ar ambient. Cross-sectional transmission electron microscopy and X-ray photoelectron spectroscopy studies showed that the implanted Ag ions were incorporated in TiO2 to form Ag2O after thermal annealing. The Ag-implanted TiO2 film with fluence of 3 × 1016 ions/cm2 after an annealing showed improved photocatalytic efficiency comparing to TiO2 film. When the implantation fluence increased to the 5 × 1016 ions/cm2, the sample showed poorer phtotcatalytic efficiency. These results indicate that there exists an optimum Ag ions implantation fluence. The photocatalytic behavior can be explained by the effect of Ag+ on the physicochemical properties in terms of electronic structures and film texture