LiNi<Subscript>0.8</Subscript>Co<Subscript>0.2−x</Subscript>Ti<Subscript>x</Subscript>O<Subscript>2</Subscript> nanoparticles: synthesis,structure, and evaluation of electrochemical properties for lithium ion cell application

Layered Ti-doped lithiated nickel cobaltate, LiNi_0.8Co_{0.2 − x}Ti_xO₂ (where x = 0.01, 0.03, and 0.05) nanopowders were prepared by wet-chemistry technique. The structural properties of synthesized materials were characterized by X-ray diffraction (XRD) and thermo-gravimetric/differential thermal analysis (TG/DTA). The morphological changes brought about by the changes in composition of LiNi_0.8Co_{0.2 − x}Ti_xO₂ particles were examined through surface examination techniques such as scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses. Electrochemical studies were carried out using 2016-type coin cell in the voltage range of 3.0–4.5 V (vs carbon) using 1 M LiClO₄ in ethylene carbonate and diethyl carbonate as the electrolyte. Among the various concentrations of Ti-doped lithiated nickel cobaltate materials, C/LiNi_0.8Co_0.17Ti_0.03O₂ cell gives stable charge–discharge features.     

Layered LiCo1?xMgxO2 (x = 0.0, 0.1, 0.2, 0.3 and 0.5) cathode materials for lithium-ion rechargeable batteries

Layered LiCo_1−x Mg _x O₂ (x = 0.0, 0.1, 0.2, 0.3 and 0.5) oxide materials were synthesized using LiNO₃, Co(NO₃)₂, Mg(NO₃)₂ as the precursors, and the effect of the dopants on the electrochemical properties was investigated. thermogravimetric/differential thermal analysis was carried out to observe the phase transformations of LiCo_0.9Mg_0.1O₂. The phase purity and cation environment of the synthesized oxides were characterized using X-ray diffraction and Fourier transform infrared spectroscopy. The particle size, nature, morphological properties and composition of the synthesized oxides were examined by TEM and SEM with energy dispersive X-ray spectroscopic analysis. Finally, the electrochemical behavior of the prepared layered materials was studied using cyclic voltammetry and charge–discharge cycling. LiCo_0.8Mg_0.2O₂ has good cycling results when compare to other doped and undoped materials. These results have been also supported by cyclic voltammograms.     

Electrochemical Preparation of Yttrium Hexacyanoferrate on Reduced Graphene Oxide and Its Application to Analgesic Drug Sensor

Herein, we report a template free and surfactant less electrochemical approach for the preparation of flower‐like yttrium hexacyanoferrate (YHCF) particles on reduced graphene oxide (RGO) modified glassy carbon electrode (GCE). The morphology of YHCF particles has been controlled by varying the molar ratio of Y(NO₃)₂ and K₃Fe(CN)₆ for the first time. The surface morphology of as‐prepared RGO/YHCF composite was characterized using SEM, EDX, IR and XRD methods. The electrocatalytic activity of the RGO/YHCF composite modified GCE towards Paracetamol (PA) oxidation has been investigated by using cyclic voltammetry (CV) and linear sweep voltammetry (LSV). Besides, the practical feasibility of the fabricated modified GCE has been demonstrated through the determination of PA from commercially purchased Paracetamol tablets.     

Dopant depends on morphological and electrochemical characteristics of LiMn 2– X Mo X O4 cathode nanoparticles

For the first time, solid solutions of LiMn_2–X Mo _X O₄ nanoparticles were synthesized by combustion method at 700 °C in air. The synthesized LiMn_2–X Mo _X O₄ (X?=?0.0–0.2) nanoparticles were characterized by X-ray powder diffraction, Fourier transform infrared spectroscopy (FT-IR), Field emission-scanning electron microscopy, and Particle size analysis. The unit-cell constant is increasing from 8.237 to 8.293 Å with the increase of Mo, the presence of Mo at X?≤?0.05 in LiMn_2–X Mo _X O₄ nanoparticles retained the spinel structure (Fd-3m), whereas on increasing the Mo (X?≥?0.05 %), the ordering of Li⁺ ions in both octahedral and tetrahedral cationic position leads to the lowering of symmetry (P4₁32). On increasing the Mo content, prominent peak splitting and broadening are observed at 600–500 and 830 cm^?1 for Li–Mn–O and Mo–O respectively in the FT-IR spectra. The TG/DTA spectrum reveals that the convenient formation of Li mangano-molybdate is at 700 °C. The voltammograms of all the samples show two redox peaks centered around 4 V except for the sample with higher Mo doping (X?=?0.2). The sample with X?=?0.03 shows higher redox peak current values. A marginal increase of 146 Ω R _ct value was found for the LiMn_1.97Mo_0.03O₄ nanomaterial after 10th cycle which is rather high for the rest of the materials. A discharge capacity retention of 88 % at 50th cycle is observed for X?=?0.03 sample, while the other samples exhibit drastically reduced capacity. The LiMn_1.97Mo_0.03O₄ nanoparticle can able to deliver higher and constant discharge capacity, and it may be a good alternative for the existing cathode materials.