University of Science and Technology Beijing

About: University of Science and Technology Beijing is a education organization based out in Beijing, China. It is known for research contribution in the topics: Microstructure & Alloy. The organization has 41558 authors who have published 44473 publications receiving 623229 citations. The organization is also known as: Beijing Steel and Iron Institute.

Multi-shelled metal oxides prepared via an anion-adsorption mechanism for lithium-ion batteries

Abstract: One of the major problems in the development of lithium-ion batteries is the relatively low capacity of cathode materials compared to anode materials. Owing to its high theoretical capacity, vanadium oxide is widely considered as an attractive cathode candidate. However, the main hindrances for its application in batteries are its poor capacity retention and low rate capability. Here, we report the development of multi-shelled vanadium oxide hollow microspheres and their related electrochemical properties. In contrast to the conventional cation-adsorption process, in which the metal cations adsorb on negatively charged carbonaceous templates, our approach enables the adsorption of metal anions. We demonstrate controlled syntheses of several multi-shelled metal oxide hollow microspheres. In particular, the multi-shelled vanadium oxide hollow microspheres deliver a specific capacity of 447.9 and 402.4mAhg(-1) for the first and 100th cycle at 1,000mAg(-1), respectively. The significant performance improvement offers the potential to reduce the wide capacity gap often seen between the cathode and anode materials.

Emerging ultra-narrow-band cyan-emitting phosphor for white LEDs with enhanced color rendition.

Abstract: Phosphor-converted white LEDs rely on combining a blue-emitting InGaN chip with yellow and red-emitting luminescent materials. The discovery of cyan-emitting (470–500 nm) phosphors is a challenge to compensate for the spectral gap and produce full-spectrum white light. Na0.5K0.5Li3SiO4:Eu2+ (NKLSO:Eu2+) phosphor was developed with impressive properties, providing cyan emission at 486 nm with a narrow full width at half maximum (FWHM) of only 20.7 nm, and good thermal stability with an integrated emission loss of only 7% at 150 °C. The ultra-narrow-band cyan emission results from the high-symmetry cation sites, leading to almost ideal cubic coordination for UCr4C4-type compounds. NKLSO:Eu2+ phosphor allows the valley between the blue and yellow emission peaks in the white LED device to be filled, and the color-rendering index can be enhanced from 86 to 95.2, suggesting great applications in full-spectrum white LEDs. Luminescent crystals that efficiently emit light in the narrow cyan color wavelength range, from 470 to 500 nanometers, could be used to fill a gap or “valley” in light-emitting diodes (LEDs) intended to mimic the full spectrum of daylight. There is great interest in developing more efficient and cost-effective full daylight spectrum LED lighting sources. These can create more natural indoor lighting conditions that are also believed to be more beneficial for health. Researchers in China and Russia, led by Zhiguo Xia at the University of Science and Technology Beijing, developed a suitable inorganic crystalline compound showing narrow cyan emission, with the formula Na0.5K0.5Li3SiO4:Eu2+. The many possible applications include LEDs for daylight spectrum lamps used to treat the low mood and depression associated with Seasonal Affective Disorder (SAD).