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15. Discovery of abnormal lithium-storage sites in molybdenum dioxide electrodes.

Author

Shon, Jeong Kuk, Lee, Hyo Sug, Park, Gwi Ok, Yoon, Jeongbae, Park, Eunjun, Park, Gyeong Su, Kong, Soo Sung, Jin, Mingshi, Choi, Jae-Man, Chang, Hyuk, Doo, Seokgwang, Kim, Ji Man, Yoon, Won-Sub, Pak, Chanho, Kim, Hansu, and Stucky, Galen D

Abstract

Developing electrode materials with high-energy densities is important for the development of lithium-ion batteries. Here, we demonstrate a mesoporous molybdenum dioxide material with abnormal lithium-storage sites, which exhibits a discharge capacity of 1,814 mAh g(-1) for the first cycle, more than twice its theoretical value, and maintains its initial capacity after 50 cycles. Contrary to previous reports, we find that a mechanism for the high and reversible lithium-storage capacity of the mesoporous molybdenum dioxide electrode is not based on a conversion reaction. Insight into the electrochemical results, obtained by in situ X-ray absorption, scanning transmission electron microscopy analysis combined with electron energy loss spectroscopy and computational modelling indicates that the nanoscale pore engineering of this transition metal oxide enables an unexpected electrochemical mass storage reaction mechanism, and may provide a strategy for the design of cation storage materials for battery systems.

Published
2016

31. Influence of surfactant on the structural, morphological and optical properties of SrWO4: Insights through electron density distribution analysis.

Author

Balu, Santhanam, Sivaganesh, D, Saravanakumar, S, Sivakumar, V, Kim, Ji-Man, Kannan, Padmanathan Karthick, and Ganesh, V

Subjects
ELECTRON density, ELECTRON distribution, OPTICAL properties, SURFACE active agents, X-ray powder diffraction
Abstract

Scheelite-type surfactant-assisted SrWO4 was prepared via a simple co-precipitation method. The effect of various surfactants such as hexamethylenetetramine, polyvinylpyrrolidone, and sodium dodecyl sulphate, on the structural, morphological and photoluminescence (PL) properties of SrWO4 was investigated. Powder X-ray diffraction and the Rietveld profile refinement technique confirmed the tetragonal structure of all the as-synthesized SrWO4 materials. Among the three surfactants, particles with spherical morphology were observed for SDS-assisted SrWO4. Surfactant-assisted SrWO4 exhibited bluish-green emission around 500 nm, ascribed to the presence of WO 4 2 - luminescence centre at 284 nm excitation, and the PL emission intensity significantly increased in the presence of surfactant. Electron density distribution analysis of a single unit cell for all the prepared materials was investigated, and correlated with the PL results. [ABSTRACT FROM AUTHOR]

Published
2023
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