3 research outputs found
The mechanism of caesium intercalation of graphene
Properties of many layered materials, including copper- and iron-based
superconductors, topological insulators, graphite and epitaxial graphene can be
manipulated by inclusion of different atomic and molecular species between the
layers via a process known as intercalation. For example, intercalation in
graphite can lead to superconductivity and is crucial in the working cycle of
modern batteries and supercapacitors. Intercalation involves complex diffusion
processes along and across the layers, but the microscopic mechanisms and
dynamics of these processes are not well understood. Here we report on a novel
mechanism for intercalation and entrapment of alkali-atoms under epitaxial
graphene. We find that the intercalation is adjusted by the van der Waals
interaction, with the dynamics governed by defects anchored to graphene
wrinkles. Our findings are relevant for the future design and application of
graphene-based nano-structures. Similar mechanisms can also play a role for
intercalation of layered materials.Comment: 8 pages, 7 figures in published form, supplementary information
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Comparison Between CVD and ALE Produced TiO2 Cathodes in Zn/(PEO)4ZnCl2/TiO2,SnO2 or ITO Galvanic Cells
The way of preparation of thin films of TiO2 is extremely important regarding its application in electronic and optoelectronic devices. We have assembled Zn/(PEO)4ZnCl2/TiO2,SnO2 or ITO rechargeable galvanic cells using CVD (chemical vapour deposition) or ALE (atomic layer epitaxy) produced TiO2 cathodes. The charge-discharge cycles were measured with a constant current in the range of 10-6 to 10-5 A for different cells. It was shown that CVD prepared TiO2 cathode is increasing capacity of the cell by allowing higher constant currents to be applied to the cell. The complex impedance measurements of the electrolyte (PEO)4ZnCl2 have been performed in the range of 1 Hz to 1 MHz and in the temperature range from 290 to 400 K by applying Zn or Sn electrodes