9 research outputs found
A Facile Surface Reconstruction Mechanism toward Better Electrochemical Performance of Li<sub>4</sub>Ti<sub>5</sub>O<sub>12</sub> in Lithium-Ion Battery
No full textThrough a facile sodium sulfide (Na2S)-assisted hydrothermal treatment, clean and nondefective surfaces are constructed on micrometer-sized Li4Ti5O12 particles. The remarkable improvement of surface quality shows a higher first cycle Coulombic efficiency (≈95%), a significantly enhanced cycling performance, and a better rate capability in electrochemical measurements. A combined study of Raman spectroscopy and inductive coupled plasma emission spectroscopy reveals that the evolution of Li4Ti5O12 surface in a water-based hydrothermal environment is a hydrolysis–recrystallization process, which can introduce a new phase of anatase-TiO2. While, with a small amount of Na2S (0.004 mol L−1 at least), the spinel-Li4Ti5O12 phase is maintained without a second phase. During this process, the alkaline environment created by Na2S and the surface adsorption of the sulfur-containing group (HS− or S2−) can suppress the recrystallization of anatase-TiO2 and renew the particle surfaces. This finding gives a better understanding of the surface–property relationship on Li4Ti5O12 and guidance on preparation and modification of electrode material other than coating or doping.RST/Fundamental Aspects of Materials and Energ
High-Density Microporous Li<sub>4</sub>Ti<sub>5</sub>O<sub>12</sub> Microbars with Superior Rate Performance for Lithium-Ion Batteries
No full textNanosized Li4Ti5O12 (LTO) materials enabling high rate performance suffer from a large specific surface area and low tap density lowering the cycle life and practical energy density. Microsized LTO materials have high density which generally compromises their rate capability. Aiming at combining the favorable nano and micro size properties, a facile method to synthesize LTO microbars with micropores created by ammonium bicarbonate (NH4HCO3) as a template is presented. The compact LTO microbars are in situ grown by spinel LTO nanocrystals. The as-prepared LTO microbars have a very small specific surface area (6.11 m2 g−1) combined with a high ionic conductivity (5.53 × 10−12 cm−2 s−1) and large tap densities (1.20 g cm−3), responsible for their exceptionally stable long-term cyclic performance and superior rate properties. The specific capacity reaches 141.0 and 129.3 mAh g−1 at the current rate of 10 and 30 C, respectively. The capacity retention is as high as 94.0% and 83.3% after 500 and 1000 cycles at 10 C. This work demonstrates that, in situ creating micropores in microsized LTO using NH4HCO3 not only facilitates a high LTO tap density, to enhance the volumetric energy density, but also provides abundant Li-ion transportation channels enabling high rate performance.RST/Fundamental Aspects of Materials and Energ
Dynamics of sugars, endogenous hormones, and oil content during the development of Camellia oleifera Abel. fruit
Full text linkCamellia oleifera Abel (‘Huashuo’) is an important woody oil species with high economic value. Low yield is the main factor restricting the rapid development of the oil-tea industry. The dynamics of sugars, oil, endogenous hormones and the genes involved in these pathways, as well as the correlation with oil synthesis-related factors in Huashuo were investigated. The results showed that oil content was positively correlated with sucrose and starch content, but negatively correlated with reducing sugar content. Pyruvate kinase (PK) and fructose-1,6-bisphosphate aldolase (FBA) of the glycolysis pathway could be beneficial for oil biosynthesis. Higher levels of acetyl CoA carboxylase (ACC), stearoyl-ACP desaturase (SAD), and WRINKLED1 (WRI1), but lower levels of omega-6 fatty acid desaturase 2 (FAD2) and lipoxygenase 5 (LOX5) could be responsible for the oil production. The higher expression of gibberellin 20 oxidase (GA20ox) but lower expression of gibberellic acid insensitive (GAI), as well as the increase in 9-cis-epoxycarotenoid dioxygenase (NCED) at the mRNA level could contribute to oil accumulation. The results of this study could provide a reference for increasing the yield of related plants.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
