http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Nb-Doped titanium phosphate for sodium storage: electrochemical performance and structural insights
Voronina, Natalia,Jo, Jae Hyeon,Choi, Ji Ung,Jo, Chang-Heum,Kim, Jongsoon,Myung, Seung-Taek The Royal Society of Chemistry 2019 Journal of Materials Chemistry A Vol.7 No.10
<P>The effect of Nb<SUP>5+</SUP> doping on the electrochemical and structural characteristics of NaTi2(PO4)3 was investigated. The Nb<SUP>5+</SUP> substitution lowered the band gap energy from 2.8 to 1.4 eV according to density functional theory calculations. Subsequent carbonization of pitch carbon on the surface of NaNbxTi2−x(PO4)3 (<I>x</I> = 0.05) significantly increased the electrical conductivity, thereby improving the capacity and high-rate capability. The excellent cyclability and superior electrode performance result from facile Na<SUP>+</SUP> insertion and extraction that occur <I>via</I> a biphasic redox mechanism, namely, the Ti<SUP>4+/3+</SUP> redox couple for the cathode and a sequence of two biphasic redox reactions associated with the Ti<SUP>3+/2+</SUP> redox couple for the anode, as revealed by <I>operando</I> X-ray diffraction and <I>ex situ</I> X-ray absorption spectroscopic studies. Moreover, the possibility of application of Na2.9Nb0.05Ti1.95(PO4)3 as both a cathode and anode material was demonstrated in a symmetric cell, which delivered a capacity of 105 mA h g<SUP>−1</SUP> after 100 cycles at 0.2C with a capacity retention of 83%.</P>
Marcasite iron sulfide as a high-capacity electrode material for sodium storage
Voronina, Natalia,Yashiro, Hitoshi,Myung, Seung-Taek The Royal Society of Chemistry 2018 Journal of materials chemistry. A, Materials for e Vol.6 No.35
<P>Iron sulfides have attracted significant attention as promising electrode materials for sodium-ion batteries (SIBs) owing to their low electronegativity, high theoretical capacity, and cost-effectiveness. However, the large size of sodium ions generally induces severe volume changes and sluggish sodium kinetics in iron sulfide electrodes, which have prevented their practical application in SIBs. Herein, an orthorhombic marcasite FeS2 was successfully synthesized under solvothermal conditions and subsequently modified using electro-conductive carbon. This report is the first to use marcasite FeS2 as an electrode material in Na cells. The FeS2/carbon composite exhibited a high Na-storage capacity with stable capacity retention in Na cells; specifically, a discharge capacity of 385 mA h g<SUP>−1</SUP> (over 85% of the initial capacity) was retained after 200 cycles at 100 mA g<SUP>−1</SUP>. The following related Na-storage mechanism was proposed: FeS2 + 2Na<SUP>+</SUP> + 2e<SUP>−</SUP> → FeS + Na2S on sodiation (reduction), and this reaction occurs reversibly on desodiation (oxidation). The FeS2 cathode in the Na cells delivered a high energy density of approximately 620 W h kg<SUP>−1</SUP> even after 200 cycles, which is comparable to that of commercial cathode materials for lithium-ion batteries.</P>
REPOSITIONING THE LUXURY FASHION INDUSTRY: A CONSUMER-BASED MODEL
Maria Voronina,Nicole Hartley,Daniela Buce 글로벌지식마케팅경영학회 2015 Global Fashion Management Conference Vol.2015 No.06
This paper utilizes a categorical approach, proposing and validating a comprehensive model that facilitates the understanding of the structure of the luxury fashion industry through the lens of the consumer. It explores the value dimensions of luxury fashion products and clarifies the confusion that is evident in the earlier luxury literature.