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In the present study, CaZrO3 nanophosphors were sensitized with lanthanum (La) at different concentrations (0.5, 1.0, 1.5, 2.0, and 2.5) prepared using polyvinyl alcohol as the chelating agent through the sol–gel method. To study their structural and optical properties, samples were characterized by X‐ray diffractometry (XRD), field emission scanning electron microscopy (FE‐SEM), transmission electron microscopy (TEM) and photoluminescence (PL). The XRD results revealed that samples were well crystallized and average crystallite sizes were calculated. The average crystallite size value was in good agreement with the value obtained from TEM analysis. Energy dispersive spectroscopy and FE‐SEM confirmed the existence of La in the prepared samples. In the PL spectra, La‐sensitized samples exhibited three bands at 402 nm, 438 nm, and 463 nm in the visible range when excited at the 260 nm wavelength. As the proportion of La increased, the intensity of bands at 438 nm and 463 nm decreased, whereas the band at 402 nm remained stable. Time‐resolved PL spectra illustrated the lifetime of the samples. Corresponding CIE co‐ordinates for La‐sensitized CaZrO3 were calculated. [ABSTRACT FROM AUTHOR]

Layer structured Li1.10(Ni0.32X0.01Co0.33Mn0.33)O2 (X = Dy/Gd/Ho) compounds were synthesized via the microwave assisted solvothermal route. The impacts of doping on the electrical and electrochemical properties of Li1.10 (Ni0.32X0.01Co0.33Mn0.33)O2 compounds were investigated. Rietveld refined XRD pattern showed Li1.10 (Ni0.32X0.01Co0.33Mn0.33)O2 compounds with layered hexagonal structure. SEM images revealed the compounds with micrometer sized grains. The Li1.10 (Ni0.33Co0.33Mn0.33)O2 compound delivered an initial discharge capacity of 197 mAh/g at 0.2C and retained a capacity of 163mAh/g after 50th cycle in the voltage window of 2.5-4.6V. The cycling stability of Li1.10(Ni0.33Co0.33Mn0.33)O2 compound was improved with rare earth doping. Li1.10(Ni0.32Dy0.01Co0.33Mn0.33)O2 compound delivered the discharge capacity of 166 mAh/g after50th cycle in the potential window 2.5-4.6V at 0.2C with 100% capacity retention. AC impedance studies displayed the electrical conductivity in the order of 10-6 S/cm. Wagner polarization analysis revealed the improvement in electronic transference number via rare earth doping. [ABSTRACT FROM AUTHOR]

Herein, preparation of Ag2ZnSnSe4 (AZTSe) thin films using physical vapor deposition followed by selenization in a quartz tube with rapid thermal process (RTP) is reported. The precursor stacks, [Sn/Se/ZnSe/Se/Ag/Se] × 4, are deposited onto the glass substrate at 100 °C using the combination of thermal and e‐beam evaporation methods. The post selenization of precursors is conducted at different temperatures (300–425 °C). The X‐ray diffraction and Raman spectra of the precursor films selenized at 400 °C reveal the formation of single‐phase AZTSe, exhibiting a kesterite structure with a preferred orientation along the (112) plane. These films show larger grains of ≈230 nm with the homogeneous distribution of Ag, Zn, Sn, and Se across the film thickness. The precursor films selenized at temperatures ≤400 °C show the fundamental absorption edge of AZTSe (Eg = 1.36–1.44 eV) as well as an additional adsorption edge (Eadd = 1.31–1.32 eV) corresponding to ZnSn + SnZn defect complex. The Hall effect measurement indicates n‐type conductivity irrespective of selenization temperature. For films selenized at 400 °C, the carrier concentration is decreased to 2.83 × 1011 cm−3 and results in a high mobility of 73.9 cm2(V s)−1, which is attributed to the reduction of SnZn defects. [ABSTRACT FROM AUTHOR]

Fast sodium ion conducting Na11Sn2PSe12 solid electrolyte was prepared by a mechanochemical method. This is the first tin based selenide prepared by room temperature ball milling instead of conventional synthesis in a sealed quartz tube under vacuum. Our approach is safe and easy to scale up. Samples were synthesized systematically using various intervals of ball milling and annealing time to maximise phase purity and ionic conductivity. The highest room temperature bulk ionic conductivity of the mechanochemically synthesized Na11Sn2PSe12 was 1.0 mS cm−1 observed for a sample prepared by ball milling for 15 h followed by 6 h annealing at 550 °C. This fast-ion conducting Na11Sn2PSe12 allowed to demonstrate the first Na–Se all-solid-state batteries Na/Na11Sn2PSe12/C–Se and Na3Sn/Na11Sn2PSe12/C–Se with specific initial discharge capacities of 430 mA h g−1 or 400 mA h g−1, respectively at a current density 0.08 mA cm−2. The Na3Sn/Na11Sn2PSe12/C–Se battery could be cycled 500 times with a capacity that decreased gradually to 50 mA h g−1. [ABSTRACT FROM AUTHOR]

The favorable combination of fast-ionic conductivity and high electrochemical stability of Li-stuffed garnet type Li7La3Zr2O12 (LLZ) makes this material a promising candidate for applications as a solid-state electrolyte in high-energy-density batteries. However, a widespread technical use of LLZ is impeded by difficulty in reliable formation and densification of the pure fast-ion conducting phase. The present study of the phase-formation process enables rational fabrication procedures to be devised based on a thorough understanding of the complex phase formation of LLZ. In situ neutron powder diffraction monitoring of the phase formation revealed an influence of the partial melting of precursors on the formation of the fast-ion conducting phase, indicating that in the typical synthesis route LLZ is not formed in a solid-state reaction but from a partial carbonate melt that decomposes on further heating. The cooling rate critically influences lithium ordering and ionic conductivity. [ABSTRACT FROM AUTHOR]