Lithium-ion (Li-ion) batteries that rely on cationic redox reactions are the primary energy source for portable electronics. One pathway toward greater energy density is through the use of Li-rich layered oxides. The capacity of this class of materials ()270 milliampere hours per gram) has been shown to be nested in anionic redox reactions, which are thought to form peroxo-like species. However, the oxygen-oxygen (O-O) bonding pattern has not been observed in previous studies, nor has there been a satisfactory explanation for the irreversible changes that occur during first delithiation. By using Li2IrO3 as a model compound, we visualize the O-O dimers via transmission electron microscopy and neutron diffraction. Our findings establish the fundamental relation between the anionic redox process and the evolution of the O-O bonding in layered oxides.the beneficial role of F-rGO separators.
COBISS.SI-ID: 5828378
In collaboration with colleagues from France, Switzerland, Belgium and India we carried out a complex study on a new cathode material for the next generation Li-ion batteries. The work, which was published in JACS, describes the complex electrochemical behavior of Li4FeSbO6 material. Using different characterization techniques we showed that the reaction mechanism connected with the change of redox state of iron and oxygen release depends on the voltage of the battery.
COBISS.SI-ID: 5685274
Electrochromic (EC) devices assembled using two complementary optically active electrodes, i.e. sputtered tungsten (VI) oxide (WO3) and sol–gel substoichiometric nickel oxide–polyaniline (NiO1−x–PANI) films, were used for the evaluation of several ormolytes during coloring/bleaching switching. Electrolytes were prepared from bis end-capped bis(ethoxysilyl)/poly(ethylene oxide) di-uretanesil precursor via solvolysis and condensation with glacial acetic acid. Different amounts of mesylate imidazolium-based ionic liquid co-solvent were added to modify the viscoelastic properties of the ormolytes. The formation and properties of prepared materials were extensively studied using IR spectroscopic investigation, 29Si NMR spectroscopy, X-ray diffraction, rheology measurements and time-dependent determination of the conductivities.
COBISS.SI-ID: 5675802
The dissolution behaviors of Ru and ruthenium oxide nanoparticles in acidic media were studied for the first time using highly sensitive in situ measurements of concentration by inductively coupled plasma mass spectrometry (ICP-MS). Online time- and potential-resolved electrochemical dissolution profiles revealed novel corrosion features (signals) in the potential window from 0 to ca. 1.4 V, where known severe dissolution due to the oxygen evolution reaction (OER) takes place. Most of the features follow the thermodynamic changes of the Ru oxidation/reduction state, which consequently trigger so-called transient dissolution. The present results are relevant for various energy-conversion and -storage devices such as proton-exchange membrane electrolyzers, low-temperature fuel cells, reverse fuel cells, supercapacitors, batteries, and photocatalysts that can contain Ru as an active component.
COBISS.SI-ID: 5687322
Titanium and titanium alloys exhibit a unique combination of strength and biocompatibility, which enables their use in medical applications accounting for their extensive use as implant materials in the last 50 years. Currently, a lot of research was performed in order to determine the optimal surface topography for use in bioapplications, and thus emphasis is on nanotechnology for biomedical applications. It was recently shown that titanium implants with rough surface topography and free energy increase the osteoblast adhesion, maturation and subsequent bone formation. Furthermore, adhesion of different cell lines to the surface of titanium implants is influenced by the surface characteristics of titanium, namely topography, charge distribution and chemistry. The present review article focuses on specific nanotopography of titanium e.g. titanium dioxide (TiO2) nanotubes, by a simple electrochemical anodization method of the metallic substrate or by other processes such as hydrothermal, sol-gel template. One key advantage of using TiO2 nanotubes in cells interactions is based on the fact that TiO2 nanotubes morphology was correlated with cell adhesion, spreading, growth, and differentiation of mesenchymal stem cells which were shown to be maximally induced on smaller diameter nanotubes (15 nm), but hindered on larger diameter (100 nm) leading to cell death/ apoptosis. Research suggested the significance of nanotopography (TiO2 nanotube diameter) in cell adhesion and cell growth, and that mechanics of focal adhesions formation is similar among different cells types. As such, the present review will focus on perhaps the most spectacular and surprising one-dimensional structures and their unique biomedical applications for increased osseointegration, protein interaction, and antibacterial properties.
COBISS.SI-ID: 28319015