In Situ Lithiated ALD Niobium Oxide for Improved Long Term Cycling of Layered Oxide Cathodes: A Thin-Film Model Study

Understanding structural defects in lithium-rich layered oxide cathodes

Planar defects in lithium-rich layered oxides were examined by aberration-corrected scanning transmission electron microscopy (STEM) to understand their formation. Planar defects were found to form during the transition of the transition metal layer from a disordered R 3m state to a lithiumordered C2/m state. This disorder-to-order transition resulted in three orientation variants, namely [100]...

Chemical Modification of Niobium Layered Oxide by Tetraalkylammonium Intercalation

A modificação química do material lamelar K 4 Nb 6 O 17 foi investigada sistematicamente através da reação de sua forma protônica (H 2 K 2 Nb 6 O 17 ) em soluções alcalinas contendo os cátions tetrametilamônio (tma), tetraetilamônio (tea) ou tetrapropilamônio (tpa). A quantidade intercalada corresponde a 50% (para tma), 25% (para tea) e 15% (para tpa) da carga negativa do H 2 K 2 Nb 6 O 17 (con...

In Situ Vibrational Spectroscopy Studies of Supported Niobium Oxide Catalysts

The IR spectra of bulk Nb2O5‚nH2O and niobia supported on SiO2, Al2O3, ZrO2, and TiO2 were recorded in the fundamental and overtone NbdO regions, as well as in the hydroxyl region, to develop a better understanding of the structural models of surface NbOx species. The coincidence of the IR and Raman fundamental NbdO frequency in Nb2O5/Al2O3, Nb2O5/ZrO2, and Nb2O5/TiO2 provides the strongest evi...

Alumina and Hafnia ALD Layers for a Niobium-Doped Titanium Oxide Photoanode

Niobium-doped titanium dioxide (TiO2) nanoparticles were used as a photoanode in dye-sensitized solar cells (DSCs). They showed a high photocurrent density due to their higher conductivity; however, a low open-circuit voltage was exhibited due to the back-reaction of photogenerated electrons. Atomic layer deposition is a useful technique to form a conformal ultrathin layer of Al2O3 and HfO, whi...

Metal Oxide Thin Films and Nanostructures Made by ALD