Search results for "nickel oxide"

Precipitation and Calcination of High-Capacity LiNiO2 Cathode Material for Lithium-Ion Batteries

2020

This article presents the electrochemical results that can be achieved for pure LiNiO2 cathode material prepared with a simple, low-cost, and efficient process. The results clarify the roles of the process parameters, precipitation temperature, and lithiation temperature in the performance of high-quality LiNiO2 cathode material. Ni(OH)2 with a spherical morphology was precipitated at different temperatures and mixed with LiOH to synthesize the LiNiO2 cathode material. The LiNiO2 calcination temperature was optimized to achieve a high initial discharge capacity of 231.7 mAh/g (0.1 C/2.6 V) with a first cycle efficiency of 91.3% and retaining a capacity of 135 mAh/g after 400 cycles. These a…

Correlation of aluminum doping and lithiation temperature with electrochemical performance of LiNi1-xAlxO2 cathode material

2022

Abstract This article presents a process for producing LiNi1-xAlxO2 (0 <  ×  < 0.05) cathode material with high capacity and enhanced cycle properties of 145 mAh/g after 600 cycles. The LiNi1-xAlxO2 (0 <  ×  < 0.05) cathode material is prepared by mixing coprecipitated Ni(OH)2 with LiOH and Al(OH)3, followed by lithiation at temperature range of 650–710 °C, after which any residual lithium from lithiation is washed from the particle surfaces. Electrochemical performance was studied within full-cell and half-cell application; in addition, different material characterization methods were carried out to explain structure changes when certain amount of aluminum is introduced in the …

Magnon and Phonon Excitations in Nanosized NiO

2019

Single-crystal, microcrystalline and nanocrystalline nickel oxides (NiO) have been studied by Raman spectroscopy. A new band at ~200 cm-1 and TO-LO splitting of the band at 350–650 cm-1 have been found in the spectra of single-crystals NiO(100), NiO(110) and NiO(111). The Raman spectra of microcrystalline (1500 nm) and nanocrystalline (13–100 nm) NiO resemble those of the single crystals. They all contain the two-magnon band at 1500 cm-1, indicating that the oxides remain at room temperature in the antiferromagnetic phase. Besides, a new sharp Raman band has been observed at 500 cm-1 in nanocrystalline NiO. Its temperature dependence suggests the magnetic origin of the band, possibly associ…

Local structure relaxation in nanocrystalline Ni1−xO thin films

2014

Abstract Non-stoichiometric nickel oxide (Ni 1 − x O) thin films were prepared by DC magnetron sputtering technique in mixed Ar/O 2 atmosphere and studied by synchrotron radiation Ni K-edge x-ray absorption spectroscopy, x-ray diffraction and scanning electron microscopy. The use of advanced modelling technique, combining classical molecular dynamics with ab initio multiple-scattering extended x-ray absorption fine structure calculations, allowed us to describe the structure relaxation and dynamics in nanocrystallites and to estimate their size and the concentration of nickel vacancies.

Antiferromagnetism and p‐type conductivity of nonstoichiometric nickel oxide thin films

2020

Plasma‐enhanced atomic layer deposition was used to grow non‐stoichiometric nickel oxide thin films with low impurity content, high crystalline quality, and p‐type conductivity. Despite the non‐stoichiometry, the films retained the antiferromagnetic property of NiO.

Solution-processed Nickel Oxide electrocatalyst for Electrochemical Water Splitting

2020

Neutron scattering study of structural and magnetic size effects in NiO

2013

Nickel oxide powders with the grain size of 13–1500 nm have been studied by neutron scattering, scanning electron microscopy and vibrating sample magnetometry. We have found that the atomic structure and the antiferromagnetic ordering are nearly independent of the average size of grains. The existence of the uncompensated spins in nanoparticles with the grain size below 100 nm has been detected.

Structural and Magnetic Properties of Nickel Oxide Nanopowders

2010

Structure and magnetic properties of nickel oxide (NiO) nanopowders have been studied by X-ray/neutron diffraction, SQUID magnetometer, and micro-Raman spectroscopy. Our diffraction data indicate that at room temperature all NiO powders are antiferromagnetically ordered and have a rhombohedral (R-3m) phase. The SQUID magnetometry and Raman spectroscopy measurements support the presence of the antiferromagnetic ordering.

Flash microwave synthesis of trevorite nanoparticles.

2008

Nickel ferrite nanoparticles have several possible applications as cathode materials for rechargeable batteries, named 'lithium-ion' batteries. In this study, NiFe{sub 2}O{sub 4} was prepared by microwave induced thermohydrolysis. The obtained nanoparticles were characterized by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), BET method, transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS). All the results show that the microwave one-step flash synthesis leads in a very short time to NiFe{sub 2}O{sub 4} nanoparticles with elementary particles size close to 4-5 nm, and high specific surfaces (close to 240 m…

Fundamental and technological aspects of the surface properties and reactivity of some metal oxides

1997

Abstract As is usually accepted for many inorganic compounds, the surface properties often play a fundamental role in the overall properties of metal oxides, in particular when the oxide materials are used in the form of fine grains. One difficulty in characterizing these surface properties is to apply the results of studies performed on ideal surfaces to the actual materials in use. A way to accept this challenge can be to successively consider initial powders, polycrystalline pellets formed after thermal or mechanical treatment of these powders and, finally, monocrystalline surfaces prepared from these powders or pellets. This principle can be applied to the study of the surface propertie…