Er³⁺and Er³⁺/Yb³⁺Ions Embedded in Nano-Structure BaTi_0.9Sn_0.1O₃: Structure, Morphology and Dielectric Properties

Barium titanate tin oxides BaTi0.9Sn0.1O3 referred to as (BTSO) doped with 0.5Er3+ and co-doped with (0.75 and 1) Yb3+ ions, were prepared using a modified sol-gel method and calcinated at 1050?C in the air for 4 h. The influence of the selected rare earth element on the structure morphology, dielectric properties behavior was investigated. From TEM micrographs, it has appeared that the particles have a spherical shape with a small size in nanoscale. The average particle size is determined both by TEM and XRD diffraction was found to be in agreement and within the range between 45.9 and 57.7 nm. The effects of Lanthanide incorporation on the evolution of these nano-crystalline structures were followed by XRD and (FTIR). The XRD patterns give rise to a single perovskite phase, while the tetragonality was found to decrease gradually with Er3+ and Er3+/Yb3+ ions, respectively. FTIR results showed enhancement of the crystallinity and the absence of carbonates upon increasing Yb3+ ions concentration from 0.75 up to 1 mol%. The dielectric and conductivity properties were found to be enhanced by the nature and the concentration of the lanthanide element (Er3+, Yb3+) in the BTSO host lattice. The Curie temperature (Tc) shifted to a lower value from 117 for BTSO: 0.5Er to 93 for BTSO: 0.5Er/1Yb and the permittivity ε’ increased from 3972 to 6071, so BTSO: 0.5Er/1Yb good crystalline material candidate for capacitors application due to its higher permittivity.

Fluorophosphates and fluorosulfates cathode materials: Progress towards high energy density sodium-ion battery

The rapid diffusion of renewable energy boosts the wide deployment of large-scale energy storage system.With the low cost and high crustal abundance,sodium-ion battery(SIB)technology is expected to become a dominant technology in that area in the future.Toward the practical application,novel cathode materials are urged to develop that show high energy density without sacrificing their cost and benignity to the environment.While the years of many studies,this still remains a huge challenge to battery scientists.In this review,we discuss recent breakthroughs in SIB cathode materials with high energy density,namely fluorphosphates and fluorosulfates.The design of materials,the crystal structure,the electrochemical performance,and the underlaying intercalation mechanism are systematically reviewed.Useful strategies and research directions are also provided to advance future high-energy,low-cost,and ecofriendly cathode materials for next generation SIB.

Effect of rare earth on physical properties of Na_(0.5)Bi_(0.5)TiO_(3)system:A density functional theory investigation

Na_(0.5)(Bi_(3/4)RE_(1/4))_(0.5)TiO_(3)(RENBT,RE=Nd,Gd,Dy,and Ho)compounds were investigated in the framework of first-principles calculations using the full potential linearized augmented plane wave(FP-LAPW)method based on the spin-polarized density functional theory implemented in the WIEN2k code.Combined charge density distribution and Ti K-edge X-ray absorption spectra reveal that the RENBT compositions with high polarization values are accompanied by a higher TiO_(6)distortion,DyNBT,and NdNBT compounds.The effect of the rare-earth elements on the polarization is confirmed experimentally with the collection of the hysteresis loops.The investigation of the electronic properties of the compounds highlights the emergence of a magnetization owing to the 4f orbital effect of the rare-earth elements.Besides,the investigation of the chemical ordering shows a short-range chemical ordering for the pure composition and an increased A-site disorder for dysprosium doped NBT system.The increased disorder may speak for increased relaxor properties in the RE doped compositions.