76 research outputs found
Synthesis of Heterogeneous Li4Ti5O12 Nanostructured Anodes with Long-Term Cycle Stability
The 0D-1D Lithium titanate (Li4Ti5O12) heterogeneous nanostructures were synthesized through the solvothermal reaction using lithium hydroxide monohydrate (Li(OH)·H2O) and protonated trititanate (H2Ti3O7) nanowires as the templates in an ethanol/water mixed solvent with subsequent heat treatment. A scanning electron microscope (SEM) and a high resolution transmission electron microscope (HRTEM) were used to reveal that the Li4Ti5O12 powders had 0D-1D heterogeneous nanostructures with nanoparticles (0D) on the surface of wires (1D). The composition of the mixed solvents and the volume ratio of ethanol modulated the primary particle size of the Li4Ti5O12 nanoparticles. The Li4Ti5O12 heterogeneous nanostructures exhibited good capacity retention of 125 mAh/g after 500 cycles at 1C and a superior high-rate performance of 114 mAh/g at 20C
ENSO Atmospheric Teleconnections and Their Response to Greenhouse Gas Forcing
This is the final version of the article. Available from AGU via the DOI in this record.El Niño and Southern Oscillation (ENSO) is the most prominent year-to-year climate fluctuation on Earth, alternating between anomalously warm (El Niño) and cold (La Niña) sea surface temperature (SST) conditions in the tropical Pacific. ENSO exerts its impacts on remote regions of the globe through atmospheric teleconnections, affecting extreme weather events worldwide. However, these teleconnections are inherently nonlinear and sensitive to ENSO SST anomaly patterns and amplitudes. In addition, teleconnections are modulated by variability in the oceanic and atmopsheric mean state outside the tropics and by land and sea ice extent. The character of ENSO as well as the ocean mean state have changed since the 1990s, which might be due to either natural variability or anthropogenic forcing, or their combined influences. This has resulted in changes in ENSO atmospheric teleconnections in terms of precipitation and temperature in various parts of the globe. In addition, changes in ENSO teleconnection patterns have affected their predictability and the statistics of extreme events. However, the short observational record does not allow us to clearly distinguish which changes are robust and which are not. Climate models suggest that ENSO teleconnections will change because the mean atmospheric circulation will change due to anthropogenic forcing in the 21st century, which is independent of whether ENSO properties change or not. However, future ENSO teleconnection changes do not currently show strong intermodel agreement from region to region, highlighting the importance of identifying factors that affect uncertainty in future model projections.S. W. Y. is supported by the KoreaMeteorological Administration Researchand Development Program under grant KMIPA2015-2112. Wenju Cai is supported by Earth System and Climate Change Hub of the Australia National Environmental Science Programme, and Centre for Southern Hemisphere Oceans Research, an international collaboration between CSIRO and Qingdao National Laboratory for Marine Sciences and Technology. B. Dewitte acknowledges supports from FONDECYT(1151185) and from LEFE-GMMC. Dietmar Dommenget is supported by ARC Centre of Excellence for Climate System Science (CE110001028)
Direct Printing Synthesis of Self-Organized Copper Oxide Hollow Spheres on a Substrate Using Copper(II) Complex Ink: Gas Sensing and Photoelectrochemical Properties
The direct printing synthesis of
metal oxide hollow spheres in
the form of film on a substrate is reported for the first time. This
method offers facile, scalable, high-throughput production and device
fabrication processes. The printing was carried out via a doctor-blade
method using Cu(II) complex ink with controllable high viscosity based
on formate–amine coupling. Following only thermal heating in
air, well-defined polycrystalline copper oxide hollow spheres with
a submicrometer diameter (≤1 μm) were formed spontaneously
while being assembled in the form of a film with good adhesion on
the substrate. This spontaneous hollowing mechanism was found to result
from the Kirkendall effect during oxidation at elevated temperature.
The CuO films with hollow spheres, prepared via direct printing synthesis
at 500 °C, led to the creation of a superior p-type gas sensor
and photocathode for photoelectrochemical water splitting with completely
hollow cores, a rough/porous shell structure, a single phase, high
crystallinity, and no organic/polymer residue. As a result, the CuO
hollow-sphere films showed high gas responses and permissible response
speeds to reducing gases and high photocurrent density compared to
conventional CuO powder films and the values previously reported.
These results exemplify the successful realization of a high-throughput
printing fabrication method for the creation of superior nanostructured
devices
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