| Today,Lithium-ion battery(LIB) cathode materials LiCoO2 are still in an unshakable mainstream position in the market during a short term. Afterall, due to expensiveness and toxicity of Cobalt,it forces us to seek its alternative candidates.Layered structure LiNixCo1-x-yMnyO2(0=x,y=1,x+y=1), of which, the most promising binary LiNi0.5Mn0.5O2 and ternary LiNi1/3Co1/3Mn1/3O2 materials, have become an hot spot.Based on the highlights of the LIB cathode materials,the synthesis methods of both spherical micrometer LiNi0.5Mn0.5O2 and nanocrystal LiNi1/3Co1/3Mn1/3O2 were studied. The effect of synthesis methods and conditions on the structure and performance were elucidated in brief.Soft chemistry methods, such as, sol-gel, "chimie douce", hydroxide precipitation, carbonate coprecipitation, were deployed to develop the effect on the properties of LiNio.5Mno.502.Comprared with the electrochemical performence of LiNi0.5Mn0.5O2 by a carbonate coprecipitation, the other three ones showed inferior. Hereafter, the best process of synthesis of binary LiNi0.5Mn0.5O2 was carried out. The metal component, thermodynamics, structure, morphology, surface value state and electrochemical performance of as-prepared oxide powers were charactered by ICP-AES, TG-DSC, XRD, SEM, FT-IR and galvanostatic charge-discharge experiments, the issues of pH values, lithiumed approach, calcination time and versatile soft chemisty synthetic routes had been addressed. It was indicated that the optimal process was obtained by calcination of carbonate for 5h in the atmosphere of air as a pH of 8 at 550℃, then it was prepared for 15h at the temprature of 900℃quenched to the room temprature in air. The rate capacity of 0.1C,0.2C,0.5C,0.8C, 1.0C was 224.0mAh/g,166.1mAh/g,138.2mAh/g,191.7mAh/g and 108.7mAh/g respectively. The discharge specific capacity of 150mAh/g was maitained for 25 cycles with the coulomb's efficiency of over 98%. The diffusion coefficient fluctuated from 10-11.5cm2/s to 10-13cm2/s.The ternary nanocrystal LiNi1/3Co1/3Mn1/3O2 was successfully synthesized by sol-gel, herein, charactered by TG-DSC, XRD, FESEM and charge-discharge tests. The calcination time, various upperlimit voltage, and other coprecipitation methods were carried out to get better electrochemical behavour. The concentration of solution, temprature, pH, stirring speed, react time were carefully controlled. Two-step calcination approach was used to synthesize LiNi1/3Co1/3Mn1/3O2 in the size range of 100nm-200nm.It showed that initial charge and discharge specific capacity was 222.38mAh/g,180.12mAh/g.160mAh/g was obtained after 30 cycles, the capacity retention rates were almost 100% up to 30 cycles, the rate capacity of 0.5C,1C,5C,10C was 142mAh/g,120mAh/g, 110mAh/g,85mAh/g, respectively. Comprared with the electrochemical performence of different upperlimit potentials, the initial capacity enhanced, but it was not also true with the cycle number elevlated. Absolutly, we can conclude that suitable voltage system was indispensible to itself. Sample diffusion coefficient as a function of various cutoff voltage and cycle number was analysized by cpacity intermittent titration technology(CITT). The diffusion coefficient of nano-LiNi1/3Mn1/3Co1/3O2 was about 10-11-10-13cm2/s. With cycle number increace, the diffusion coefficient increased relatively at the same depth of charge(DOC), which suggested that the materials itself had an incredible ability of self-reinforcement. The diffusion coefficient was decreaced at first,then increaced slowly,decreased lastly. The trendency of the diffusion coefficient and electrochemical performance was identifical from each other.this law was also proved by PITT. We also obtained LiNi1/3Co1/3Mn1/3O2 sintered for 12h at 850℃by carbonate coprecipitation,the battery charge-discharge tests yielded that it delivered an initial discharge capacity of 200mAh/g at 0.05C rate (1C=200mAh/g) in the potential region of 2.5-4.5V vs. lithium, and remained as high as 170mAh/g in the 30th cycle.
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