Search

Your search keyword '"Pitňa Lásková, Barbora"' showing total 9 results
Start Over Author "Pitňa Lásková, Barbora"
9 results on '"Pitňa Lásková, Barbora"'

8. Electrochemical, photoelectrochemical and spectroelectrochemical characterization of nanomaterials

Author

Pitňa Lásková, Barbora, Kavan, Ladislav, Šubrt, Jan, and Krýsa, Josef

Abstract

Titanium dioxide (TiO2) and spinel Li4Ti5O12 belong to widely studied semiconducting metal oxides. Nanocrystalline TiO2 and Li4Ti5O12 are attractive materials for applications in Li-ion batteries and the former also for photoelectrochemical solar cells. Moreover, spinel Li4Ti5O12 could be a promising material for Na-ion batteries too, because of possible accommodation of larger Na+ ions (compared to Li+ ). The nanocrystalline TiO2 anatase with a predominant {001} facet was studied electrochemically by cyclic voltammetry of Li+ insertion and by chronoamperometry and compared with anatase materials with dominating {101} facet. Both voltammetric and chronoamperometric diffusion coefficients and activation energies proved higher activity of anatase {001} nanosheets toward Li+ insertion than that of the usual anatase nanoparticles exposing the {101} facet. Subsequently, the flatband potential and electron kinetics of TiO2 anatase nanocrystals with mostly exposed facet {101} or {001} were compared. The anatase {001} nanoplatelets exhibited more negative flatband potential, higher chemical capacitance and longer electron lifetime than anatase {101} nanoparticles. The Li+ insertion into TiO2 anatase nanoparticles was studied by Raman spectroscopy and by in situ Raman spectroelectrochemistry. Four...

Published
2017

9. Electrochemical performance of sol-gel-made Na2Ti3O7 anode material for Na-ion batteries.

Author

Zukalová, Markéta, Pitňa Lásková, Barbora, Mocek, Karel, Zukal, Arnošt, Bouša, Milan, and Kavan, Ladislav

Subjects
*ELECTROCHEMICAL analysis, *SOL-gel processes, *SODIUM compounds, *SODIUM ions, *STORAGE batteries, *NANOCRYSTALS
Abstract

Nanocrystalline Na2Ti3O7 material is prepared by a newly developed sol-gel procedure. The sol-gel made Na2Ti3O7 calcined at 500 °C possesses mesoporous structure and BET surface area of 89 m2 g−1. X-ray diffraction and scanning electron microscopy confirm the presence of sintered nanosheets or very small crystals of the size of 10-20 nm with short-range ordering. Electrochemical behavior of nanocrystalline Na2Ti3O7 is evaluated by cyclic voltammetry of Na insertion and by galvanostatic chronopotentiometry at different charging rates. The sol-gel made Na2Ti3O7 exhibits improved performance as compared to that of the microcrystalline Na2Ti3O7 prepared by solid-state synthesis. Discharge capacities of optimized material at charging rates 1, 2, and 5C reach 109, 86, and 63 mAh g−1, respectively, with 100% coulombic efficiency and zero capacity drop over 50 cycles after initial conditioning. Excellent performance of Na2Ti3O7_500 is obviously an effect of its large surface area giving rise to predominantly capacitive mechanism of charge storage. Hence, sol-gel made nanocrystalline Na2Ti3O7 represents promising anode material for Na-ion batteries due to its charge capacity and outstanding cycling stability.ᅟ [ABSTRACT FROM AUTHOR]

Published
2018
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results