RESUMO
Fine-tuning of particle size and morphology has been shown to result in differential material performance in the area of secondary lithium-ion batteries. For instance, reduction of particle size to the nanoregime typically leads to better transport of electrochemically active species by increasing the amount of reaction sites as a result of higher electrode surface area. The spinel-phase oxide LiNi0.5Mn1.5O4 (LNMO), was prepared using a sol-gel based template synthesis to yield nanowire morphology without any additional binders or electronic conducting agents. Therefore, proper experimentation of the nanosize effect can be achieved in this study. The spinel phase LMNO is a high energy electrode material currently being explored for use in lithium-ion batteries, with a specific capacity of 146 mAh/g and high-voltage plateau at â¼4.7 V (vs Li/Li(+)). However, research has shown that extensive electrolyte decomposition and the formation of a surface passivation layer results when LMNO is implemented as a cathode in electrochemical cells. As a result of the high surface area associated with nanosized particles, manganese ion dissolution results in capacity fading over prolonged cycling. In order to prevent these detrimental effects without compromising electrochemical performance, various coating methods have been explored. In this work, TiO2 and Al2O3 thin films were deposited using atomic layer deposition (ALD) on the surface of LNMO particles. This resulted in effective surface protection by prevention of electrolyte side reactions and a sharp reduction in resistance at the electrode/electrolyte interface region.
RESUMO
Fatty acid analysis is essential to a broad range of applications including those associated with the nascent algal biofuel and algal bioproduct industries. Current fatty acid profiling methods require lengthy, sequential extraction and transesterification steps necessitating significant quantities of analyte. We report the development of a rapid, microscale, single-step, in situ protocol for GC-MS lipid analysis that requires only 250 µg dry mass per sample. We furthermore demonstrate the broad applications of this technique by profiling the fatty acids of several algal species, small aquatic organisms, insects and terrestrial plant material. When combined with fluorescent techniques utilizing the BODIPY dye family and flow cytometry, this micro-assay serves as a powerful tool for analyzing fatty acids in laboratory and field collected samples, for high-throughput screening, and for crop assessment. Additionally, the high sensitivity of the technique allows for population analyses across a wide variety of taxa.
