We report herein on the synthesis of “layered-layered” integrated
xLi2MnO3⋅(1−x)LiMn1/3Ni1/3Co1/3normalO2
materials (
x=0.3
, 0.5, and 0.7) using the self-combustion reaction in solutions containing metal nitrates and sucrose. The nanoparticles of these materials were obtained by further annealing of the as-prepared product in air at
700°C
for 1 h and submicrometric particles were obtained by further annealing at
900°C
for 22 h. The effect of composition on the electrochemical performance was explored in this work. By a rigorous study with high resolution transmission electron microscopy (HRTEM), it became clear that the syntheses with the above stoichiometries produce two-phase materials comprising nanodomains of both rhombohedral
LiNiO2
-like and monoclinic
Li2MnO3
structures, which are closely integrated and interconnected with one another at the atomic level. Stable reversible capacities
∼220mAh/g
were obtained with composite electrodes containing submicrometer particles of
0.5Li2MnO3⋅0.5LiMn1/3Ni1/3Co1/3normalO2
. Structural aspects, activation of the monoclinic component, and stabilization mechanisms are thoroughly discussed using Raman spectroscopy, solid-state NMR, HRTEM, and X-ray diffraction (including Rietveld analysis) in conjunction with electrochemical measurements. This work provides a further indication that this family of integrated compounds contains the most promising cathode materials for high energy density Li-ion batteries.
We report on a rigorous comparative study of nano-and microparticles of LiMn 1.5 Ni 0.5 O 4 spinel as cathode materials for Li-ion batteries. The stability of these materials in LiPF 6 /alkyl carbonate solutions in temperatures up to 70°C was explored. Capacity, cycling, rate capabilities, and impedance behavior were also studied. The methods included X-ray diffraction, Raman, X-ray photelectron, Fourier transform infrared, and electron paramagnetic resonance spectroscopies, and electron microscopy, in conjunction with standard electrochemical techniques: voltammetry, chronopotentiometry, and impedance spectroscopy. These materials show an impressive stability in solutions at elevated temperature. The use of nanomaterials was advantageous for obtaining a better rate capability of LiMn 1.5 Ni 0.5 O 4 electrodes. LiMn 1.5 Ni 0.5 O 4 particles develop a unique surface chemistry in solutions that passivates and protects them from detrimental interactions with solution species at elevated temperatures.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.