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LiCoO2 and LiMn2O4 compounds were synthesized using two different methods, viz., low-temperature-aided hydrothermal and high-temperature-assisted
co-precipitation method. Keeping the reaction parameters such as type of precursors chosen and the medium of reaction as same
for both the hydrothermal and co-precipitation methods, the effect of temperature in producing LiCoO2 and LiMn2O4 with varying physical as well as electrochemical properties has been studied. As expected, the effect of low-temperature-involved
hydrothermal method rendered finer particles of nanocrystalline nature with minimum strain, and the high-temperature synthesis
of co-precipitation method produced slightly enhanced particle size with an increased strain value. The effect of size-grown
particles resulting from co-precipitation method exhibited inferior electrochemical properties such as increasing resistance
of the cell upon cycling and a significant decline in capacity behavior, irrespective of LiCoO2 or LiMn2O4 cathodes. On the other hand, hydrothermal synthesis of LiCoO2 and LiMn2O4 has exhibited acceptable specific capacity with an admissible capacity fade behavior and negligible internal resistance of
the cell, thus qualifying the same as better-performing cathodes. Hence, the effect of low temperature in producing LiCoO2 and LiMn2O4 cathodes with facile intercalation and de-intercalation of lithium is demonstrated. 相似文献
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Bhuvaneswari D. Gangulibabu Kalaiselvi N. 《Journal of Solid State Electrochemistry》2012,16(11):3667-3674
Journal of Solid State Electrochemistry - Layered LiNi y Mn y Co1 − 2y O2 [y = 0.5, 0.45, and 0.4] compounds with interconnected spherical particles are synthesized using a novel... 相似文献
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Gangulibabu D. Bhuvaneswari N. Kalaiselvi 《Applied Physics A: Materials Science & Processing》2009,96(2):489-493
A new category of lithium intercalating cathode candidates, namely LiCrP2O7, was synthesized at 800°C using a citric acid assisted modified (CAM) sol–gel method and examined for possible lithium insertion
behavior. The formation of a phase pure and monoclinic LiCrP2O7 compound with finer crystallite size was confirmed from the X-ray diffraction patterns. The presence of nano-sized particles
as observed from a transmittance electron microscope image of LiCrP2O7 and the presence of a preferred local cation environment, evidenced from Fourier transform infra-red and 7Li nuclear magnetic resonance studies, are the added advantages of the present study. Further, cyclic voltametry study performed
on 2016 coin cells consisting of the synthesized LiCrP2O7 cathode revealed an excellent cycling reversibility and structural stability. Hence, CAM sol–gel synthesized LiCrP2O7 is found to possess desirable physical as well as electrochemical properties, leading one to consider the same as a possible
lithium intercalating cathode material. 相似文献
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In a novel attempt to exploit corn starch as gelling agent (in sol–gel method) and combustible fuel (in solution-assisted combustion method), high-capacity LiMn0.4Ni0.4Co0.2O2 and LiMn1/3Ni1/3Co1/3O2 cathode materials have been prepared and a comparison of electrochemical performance of the same has been made. Among the two compounds chosen for the study, LiMn1/3Ni1/3Co1/3O2 exhibits better physical and electrochemical properties. Particularly, LiMn1/3Ni1/3Co1/3O2 cathode synthesized using corn starch-assisted combustion method exhibits an appreciable capacity of 176 mAh g?1, excellent capacity retention of 93 % up to 100 cycles and susceptible to rate capability test up to 1 C rate, thus qualifying the same for high-capacity and high-rate lithium battery applications. The study demonstrates the possibility of exploiting corn starch as gelling agent and as a combustible fuel in synthesizing lithium intercalating oxide compounds with improved electrochemical behaviour. 相似文献
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N. Jayaprakash N. Kalaiselvi Gangulibabu D. Bhuvaneswari 《Journal of Solid State Electrochemistry》2011,15(6):1243-1251
A study on the structural and electrochemical properties of LiCr0.2Mn1.8O4 and LiV0.2Cr0.2Mn1.6O4 cathodes has been made with a view to understand the effect of mono- (Cr) and bication (Cr and V) substitution on LiMn2O4 spinel individually. Citric acid assisted modified sol–gel method has been followed to synthesize a series of LiMn2O4, LiCr0.2Mn1.8O4, and LiV0.2Cr0.2Mn1.6O4 cathodes, and the corresponding lattice structure, surface morphology, and site occupancy of lithium in the spinel matrix
are acknowledged using X-ray diffraction, scanning electron microscopy, and magic angle spinning 7Li nuclear magnetic resonance results. The site occupancy of Cr3+ in the 16d octahedral and that of V5+ in the 16d octahedral and 8a tetrahedral positions are understood. Electrochemical cycling studies of LiCr0.2Mn1.8O4 cathode demonstrate an enhanced structural stability and better capacity retention (94%) resulting from the Cr3+ dopant-induced co-valency of Li-O-Mn bond. On the other hand, simultaneous substitution of Cr and V in LiV0.2Cr0.2Mn1.6O4 has failed to improve the electrochemical properties of native LiMn2O4 spinel cathode, mainly due to vanadium-driven cation mixing and the reduced lithium diffusion kinetics. Among the candidates
chosen for the study, LiCr0.2Mn1.8O4 qualifies itself as a better cathode for rechargeable lithium battery applications. 相似文献
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Gangulibabu D. Bhuvaneswari N. Kalaiselvi N. Jayaprakash P. Periasamy 《Journal of Sol-Gel Science and Technology》2009,49(2):137-144
The emerging category cathode candidates such as LiCoPO4 and LiNiPO4 were synthesized at 800 °C using Citric acid assisted modified sol–gel (CAM sol–gel) method and examined for possible lithium
intercalation behavior. Compound formation temperature is confirmed from thermogravimetry and differential thermal analysis
(TG/DTA). Powder X-ray diffraction (PXRD) pattern evidenced the absence of undesirable peaks and confirmed the formation of
phase pure LiMPO4 (M=Co, Ni) compounds with an orthorhombic structure and finer crystallite size. Presence of nanosized particles as observed
from TEM image of LiCoPO4 and the presence of preferred local cation environment as understood from FT–IR studies are the added advantages of CAM sol–gel
synthesis. Further, Cyclic voltametry (CV) and Impedance spectroscopy (EIS) studies performed on the synthesized LiCoPO4 and LiNiPO4 cathodes revealed excellent reversibility and structural stability of CAM sol–gel synthesized cathodes, especially upon storage
as well as during cycling. 相似文献
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