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Cathode material Li [Li0.2Ni0.2Co0.08Mn0.52−xCux]O2 (x = 0, 0.01, 0.03, 0.05, 0.07) has been synthesized via carbonate coprecipitation method and modified by Cu2+ which was introduced at different stages. The crystal structure features, morphology, and electrochemical properties of the powders are studied in detail using X-ray diffraction spectroscopy, scanning electron microscopy, EDS spectroscopy, and electrochemical measurements. The experimental results show that the electrochemical properties of Li [Li0.2Ni0.2Co0.08Mn0.52−xCux]O2 (x = 0, 0.01, 0.03, 0.05, 0.07) oxides are improved. This is because an appropriate amount of Cu2+ doping increases the lattice spacing of the layered material, reduces the agglomeration of the particles, and improves the uniformity of the particles. Especially in the coprecipitation stage, Cu2+ was introduced and x = 3% showed better rate and cycle performance. The specific discharge capacity at 1C and 2C was 197.28 mAhg−1 and 124.92 mAhg−1, respectively, and cycle returned to 0.1C capacity after 45 cycles, the discharge specific capacity is still up to 261.5 mAhg−1. [ABSTRACT FROM AUTHOR]

In this paper, LiMn1−xMgxPO4·Li3V2(PO4)3/C (x = 0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.10) and LiMnPO4·Li3V2−yAly(PO4)3/C (y = 0.01, 0.02, 0.03, 0.05, 0.07, 0.10) composite cathode materials for lithium-ion batteries were successfully synthesized by a simple sol-gel method and modified by Mg2+ doped and Al3+ doped. The effects of Mg2+ and Al3+ doping on the microstructure and electrochemical properties of LiMnPO4·Li3V2(PO4)3/C were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), EDAS energy spectrum analysis (EDS), constant current charge/discharge electrical test, cyclic voltammetry, and electrochemical impedance spectroscopy (EIS). The analysis shows that the electrochemical properties of samples have been greatly improved. The results show that when x = 0.06 and y = 0.02, the material has the best electrochemical performance. Under the voltage range of 2.5–4.5 V, the initial discharge specific capacity at 0.1 C (1 C = 143 mAh g−1) is as high as 148.2 mAh g−1 and 134.4 mAh g−1, respectively. [ABSTRACT FROM AUTHOR]

The samples of xLi3V2(PO4)3·yLiFe0.8Mn0.2PO4/C (x:y = 1:0, 3:1, 1:1, 1:2, 0:1) are facilely prepared via a ball milling-assisted two-step sintering route. According to the results of Rietveld refinement, the xLi3V2(PO4)3·yLiFe0.8Mn0.2PO4/C (x, y ≠ 0) composites are composed of orthorhombic LiFe0.8Mn0.2PO4 and monoclinic L3V2(PO4)3. Electrochemical tests show that the faster reaction kinetics improve the electrochemical properties of the xLi3V2(PO4)3·yLiFe0.8Mn0.2PO4/C (x, y ≠ 0) composites, in which all multiphase composites release more than capacity of 100 mAh g−1 at 2C at the potential range of 2.5-4.5 V. In particular, the diffusion coefficient of lithium ion is in the magnitude of 10−7 to 10−9 cm2 s−1; Li3V2(PO4)3·2LiFe0.8Mn0.2PO4/C shows the highest specific capacity at the rate range of 0.1-2C and exhibits excellent long-term rate performance with capacity retention of 93.4% (relative to the initial discharge capacity) after 280 cycles at the rate of 5C. [ABSTRACT FROM AUTHOR]

The dielectronic recombination of Li-like Xe (2s) ions was studied using the flexible atomic code based on the relativistic configuration interaction method. The resonance energies, radiative and autoionization rates, and resonance strengths were calculated systematically for the doubly excited states (2 p n l )( n = 18−32) and (2 p n′ l )( n′ = 9−27) of Be-like Xe ions. For the higher Rydberg resonance states with n ≥ 33 and n′ ≥ 28, the resonance energies and strengths were obtained by extrapolation based on quantum defect theory. The theoretical rate coefficients, covering the center-of-mass energy range 0-505 eV, are in a better agreement with the experimental results measured at the heavy-ion storage ring ESR than the Multi-Configuration Dirac-Fock calculations, especially at the resonance energy range close to the series limits. Graphical abstract: [ABSTRACT FROM AUTHOR]

Hot compression of TC8M-1 was carried out under isothermal working conditions with temperature from 1173 K to 1323 K (900 °C to 1050 °C), strain rate from 0.001 to 10/s, and height reduction from 20 to 80 pct (corresponding true strain from 0.22 to 1.61). Constitutive equations were constructed and apparent activation energies of 149.5 and 617.4 kJ/mol were obtained for deformation in the β and upper α/ β phase regions, respectively. Microstructure examination confirmed the dominant role of dynamic recrystallization in the α/ β phase region and that of dynamic recovery in the β phase region, with the occurrence of grain boundary sliding at very low strain rate (0.001/s) in both regions. Based on the dynamic materials model, processing maps were constructed, providing optimal domains for hot working at the temperature of 1253 K (980 °C) and the strain rate of 0.01 to 0.1/s, or at 1193 K to 1213 K (920 °C to 940 °C) and 0.001/s. Moreover, our results indicated that the initial temperature non-uniformity along the specimen axis before compression existed and influenced the strain distribution, which contributed to the abnormal oscillations and/or abrupt rise-up of true stress and inhomogeneous deformation. [ABSTRACT FROM AUTHOR]