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Two types of lithium cobalt oxides (LiCoO 2 ) as cathode materials for lithium ion batteries are synthesized from two cobalt sources of different facial-shapes (octahedral and truncated-octahedral Co 3 O 4 ) and Li 2 CO 3 using solid state synthesis. From X-ray diffraction and scanning electron microscopy measurements, the reaction mechanism of the formation of LiCoO 2 is investigated. It is revealed that LiCoO 2 from octahedral Co 3 O 4 with only {111} surfaces grows in one direction whereas the crystal orientation of LiCoO 2 from truncated-octahedral Co 3 O 4 with {111} and {100} surfaces is not unique and the spinel intermediates of Li x Co 2 O 4 are formed during synthesis. They show largely unequal rate and cycling performances for lithium ion battery, even though their outer appearances are nearly identical. Almost single-crystalline LiCoO 2 from octahedral precursors shows much better electrochemical performances than LiCoO 2 from truncated-octahedral precursors as a lithium ion battery cathode. By studying crystal orientation, it is shown that the poor electrochemical performances of LiCoO 2 from truncated-octahedral Co 3 O 4 are originated by crystal-mismatch between crystallites. [ABSTRACT FROM AUTHOR]

Abstract: Subcritical water could be an excellent alternative to organic solvent as a medium for extracting flavonol quercetin, due to its temperature-dependent selectivity, safety, efficiency of recovery, and lower cost. This study investigated the application of subcritical water extraction (SWE) of quercetin from onion skin and evaluated the effect of key operation conditions by varying the temperature (100–190°C), extraction time (5–30min), and mixture ratio of onion skin and diatomaceous earth (DE) (0.5:3.5–2:2) under high pressure (90–131bar). The maximum yield of quercetin (16.29±0.75mg/g onion skin) was obtained at extraction temperature of 165°C, extraction time of 15min, mixture ratio of 1.5:2.5 for onion skin and DE. The SWE was compared with three conventional extraction methods in terms of the efficiency. The quercetin yield by SWE was over eight-, six-, and fourfold greater than those obtained using the ethanol, methanol, and water-at-boiling-point extraction methods, respectively. [ABSTRACT FROM AUTHOR]