•MnCo2O4 nanowire array is prepared by a fast and facile hydrothermal method.•MnCo2O4 nanowire array exhibits noticeable pseudocapacitive properties.•The as-prepared nanowire array is also a ...promising material for Li-ion batteries.
One-dimension MnCo2O4 nanowire arrays are synthesized on nickel foam by a facile hydrothermal method. The MnCo2O4 nanowires are highly crystalline with an average diameter of 70nm and exhibit excellent properties for electrochemical energy storage. Impressively, the MnCo2O4 nanowire array exhibits noticeable pseudocapacitive performance with a high capacitance of 349.8 F g−1 at 1 A g−1 and 328.9 F g−1 at 20 A g−1 as well as excellent cycling stability. As an anode material for Li-ion batteries, the MnCo2O4 nanowire array delivers an initial specific discharge capacity of 1288.6 mAh g−1 at 100mAg−1, with reversible capacity retention of 92.7% after 50 cycles. The outstanding electrochemical performances are mainly attributed to its nanowire array architecture which provides large reaction surface area, fast ion and electron transfer and good structure stability.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
► MgO is well coated on LiLi0.2Mn0.54Ni0.13Co0.13O2 by melting impregnation method. ► The 2wt.% coated sample exhibits initial capacity of 260.8mAhg−1 at 0.1C. ► Capacity retention of 96.4% is ...obtained at 1C (200mAg−1) after 100 cycles at 25°C. ► 94.3% of capacity is retained after 50 cycles at 1C after 50 cycles at 60°C.
MgO-coated LiLi0.2Mn0.54Ni0.13Co0.13O2 was synthesized via melting impregnation method followed by a solid state reaction. Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) show that the MgO layer is well coated on the surface of the layered oxide particles. Although the initial discharge capacity of LiLi0.2Mn0.54Ni0.13Co0.13O2 with proper MgO modification decreases compared to the bare one, the 2wt.% MgO coated cathode exhibits the excellent cycling stability with capacity retention of 96.4% at a current density of 200mAg−1 after 100 cycles at room temperature and 94.3% after 50 cycles at 60°C. Electrochemical impedance spectroscopy (EIS) shows that the thin MgO layer mainly reduces the charge transfer resistance and stabilizes the surface structure of active material during cycling. Melting impregnation method is promising for MgO coating to improving the cycling stability of Li-rich layered oxide cathode for Li-ion batteries.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Cube-like and plate-like LiLi0.2Mn0.54Ni0.13Co0.13O2 particles are obtained after treated in LiCl and KCl molten salts at 800 °C, respectively, comparing to the ball-like original particles calcined ...in air. The oxide treated in KCl molten salt with large specific area of 17.05 m2 g−1 delivers high discharge capacities of 254.1 mAh g−1 and 168.5 mAh g−1 at current densities of 200 mA g−1 and 2000 mA g−1, respectively. In addition, enhanced cycle stability with capacity retention of 94.9% after 80 cycles at charge–discharge current densities of 200 mA g−1 is obtained for the oxide treated in LiCl molten salt with sacrifice of a little capacity. Such electrochemical performance change is proved to be independent of Li+ diffusion coefficient. It appears that the treatment in molten salts can effectively reform the electrochemical performances of LiLi0.2Mn0.54Ni0.13Co0.13O2 cathode materials for various applications.
•Cube and plate-like particles are obtained after treated in LiCl and KCl molten salts.•Oxide treated in KCl molten salt has large specific area of 17.05 m2 g−1.•And discharge capacity of 168.5 mAh g−1 is obtained at 10 C.•Oxide treated in LiCl molten salt has enhanced capacity retention of 94.9%.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Here, in an analysis of a 2.92 fb–1 data sample taken at 3.773 GeV with the BESIII detector operated at the BEPCII collider, we measure the absolute decay branching fractions to be B(D0 → K–e+νe) = ...(3.505 ± 0.014 ± 0.033)% and B(D0 → π–e+νe) = (0.295 ± 0.004 ± 0.003)%. From a study of the differential decay rates we obtain the products of hadronic form factor and the magnitude of the CKM matrix element $f$ $^{K}_{+}$(0)|Vcs| = 0.7172 ± 0.0025 ± 0.0035 and $f$ $^{π}_{+}$(0)|Vcd| = 0.1435 ± 0.0018 ± 0.0009.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
The cross section of the process e+e−→K+K− is measured at a number of center-of-mass energies s from 2.00 to 3.08 GeV with the BESIII detector at the Beijing Electron Positron Collider (BEPCII). The ...results provide the best precision achieved so far. A resonant structure around 2.2 GeV is observed in the cross section line shape. A Breit-Wigner fit yields a mass of M=2239.2±7.1±11.3 MeV/c2 and a width of Γ=139.8±12.3±20.6 MeV, where the first uncertainties are statistical and the second ones are systematic. In addition, the timelike electromagnetic form factor of the kaon is determined at the individual center-of-mass energy points.
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The cross section for the process e^{+}e^{-}→π^{+}π^{-}J/ψ is measured precisely at center-of-mass energies from 3.77 to 4.60 GeV using 9 fb^{-1} of data collected with the BESIII detector operating ...at the BEPCII storage ring. Two resonant structures are observed in a fit to the cross section. The first resonance has a mass of (4222.0±3.1±1.4) MeV/c^{2} and a width of (44.1±4.3±2.0) MeV, while the second one has a mass of (4320.0±10.4±7.0) MeV/c^{2} and a width of (101.4_{-19.7}^{+25.3}±10.2) MeV, where the first errors are statistical and second ones are systematic. The first resonance agrees with the Y(4260) resonance reported by previous experiments. The precision of its resonant parameters is improved significantly. The second resonance is observed in e^{+}e^{-}→π^{+}π^{-}J/ψ for the first time. The statistical significance of this resonance is estimated to be larger than 7.6σ. The mass and width of the second resonance agree with the Y(4360) resonance reported by the BABAR and Belle experiments within errors. Finally, the Y(4008) resonance previously observed by the Belle experiment is not confirmed in the description of the BESIII data.
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