Structural and magnetic properties of Sb3+ ions doped Ni-Ba-Co ferrite prepared by sol-gel method

Abstract

In the present work, nanocrystalline Sb3+ ions doped Ni0.2Ba0.1Co0.7Fe2−xSbxO4 (0 ≦ x ≦ 0.1, step by 0.025) ferrites were prepared via sol-gel method. The spinel-phase structure of samples can be confirmed by X-ray diffraction (XRD) patterns. The composition and structure were further studied by fourier transform infrared spectroscopy (FTIR). There were two typical characteristic bands ν1 and ν2 related to the stretching vibrations in spinel ferrite in FTIR spectra. Energy dispersive spectrometer (EDS) analyzed the elements of samples. It indicated that the elements of Ni, Ba, Co, Fe, O and Sb existed in the samples. Vibrating sample magnetometer was used to characterize magnetic properties. The saturation magnetization decreased from 57.65 emu/g to 44.50 emu/g with the increasing Sb3+ ions content, which is attributed to Fe3+ ions replaced by the Sb3+ ions. Remanent magnetization and coercivity first decreased and then increased slightly.

Improvement of structural and electrochemical properties of NMC layered cathode material by combined doping and coating

“…The calculated c/a ratio, higher than 4.9, confirms a well-ordered hexagonal structure. The I(003)/I(104) value is over 1.2 for both samples, which is evidence of small cation mixing (for m-NMC is slightly higher, therefore lower capacity decay and better cycling behaviors are to be expected for m-NMC [5], as well as a faster diffusion of Li + between [MO 2 ] layers because of the larger unit cell volume).…”

“…Currently, LiCoO 2 is the most commercially used intercalationtype cathode material for Li-ion batteries, due to its high operating voltage, high theoretical specific capacity, good cycling performance and ease of preparation [1,3,4]. However, the cost of cobalt and the toxicity of the material, in addition to the poor thermal stability, push to develop positive electrodes with possible alternative materials [1,5,6]. Current efforts in the area, focused on the improvement of cathode materials, resulted in the formulation of the ternary oxides LiNi a Co b Mn c O 2 (where a + b + c =1), also called NMC.…”