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A technique of combination of vacuum firing and water quenching was applied to the synthesis of LiFePO4 powder. The sample was prepared by heating the pre-decomposed precursor mixtures sealed in vacuum quartz-tube, followed by water quenching at the sintering temperature. The synthetic conditions were optimized by orthogonal experiment. The results indicate that the fast quenching treatment can avoid the overgrowth of single crystal and improve its availability ratio of active material. The sintering temperature has the greatest effect on the electrochemical performance of sample. Next is the molar ratio of Li to Fe and the sintering time, respectively. The samples prepared in the optimized technical condition has the highest reversible discharge specific capacity of 149.8 mA·h/g. 相似文献
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Influence of Ti^4+ doping on electrochemical properties of LiFePO4/C cathode material for lithium-ion batteries 总被引:2,自引:0,他引:2
To improve the performance of LiFePO4, single phase Li1-4xTixFePO4/C (x=0, 0.005, 0.010, 0.015) cathodes were synthesized by solid-state method. A certain content of glucose was used as carbon precursor and content of carbon in every final product was about 3.5%. The samples were characterized by X-ray diffraction(XRD), scanning electron microscopy observations(SEM), charge/discharge test, carbon analysis and electrochemical impedance spectroscopy(EIS). The results indicate that the prepared samples have ordered olivine structure and doping of the low concentration Ti~(4+) does not affect the structure of the samples. The electrochemical capabilities evaluated by charge-discharge test show that the sample with 1% Ti~(4+) (molar fraction) has good electrochemical performance delivering about an initial specific capacity of 146.7 mA·h/g at 0.3C rate. Electrochemical impedance spectroscopy measurement results show that the charge transfer resistance of the sample could be decreased greatly by doping an appropriate amount Ti~(4+). 相似文献
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LiFePO4 was prepared by heating the pre-decomposed precursor mixtures sealed in vacuum quartz-tube. Three kinds of cooling modes including nature cooling, air quenching, and water quenching were applied to comparing the effects of cooling modes on the microstructure and electrochemical characteristics of the material. The results indicate that the water quenching mode can control overgrowth of the grain size of final product and improve its electrochemical performance compared with nature cooling mode and air quenching mode. The sample synthesized by using water quenching mode is of the highest reversible discharge specific capacity and the best cyclic electrochemical performance, demonstrating the first discharge capacity of 138.1 mA·h/g at 0.1C rate and the total loss of capacity of 3.11% after 20 cycles. 相似文献
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正极材料LiNi1/3Co1/3Mn1/3O2的研究进展 总被引:1,自引:0,他引:1
介绍了LiNi1/3Co1/3Mn1/3O2的晶体结构和作为锂离子电池正极材料的电化学反应特征,总结了合成条件和制备方法对其物理性能和电化学性能的影响,以及不同掺杂元素(B,F,Mg,Fe,Al,Si等)对其的改性作用. 相似文献
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Synthesis of LiFePO4/C composite electrode with enhanced electrochemical performance 总被引:3,自引:1,他引:3
1 INTRODUCTION The ever-growing demand for portable batter- ies with high energy density is exerting pressure for the development of advancedlithium-ion batter- ies . Commercial Li-ion batteries rely on the appli- cation of one of the well-known lithiuminsertion hosts ,i .e . LiCoO2, Li Mn2O4and Li Ni O2. How- ever the high cost of cobalt resource ,low specific capacity of Li Mn2O4and Li Ni O2is known to be difficult to synthesize and its multi-phase reaction during electrochemical … 相似文献
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因高镍三元锂离子电池具有高能量密度而成为海内外中高端车企共同选择的对象。然而,三元正极在循环过程中会经历从H2到H3的相变而导致较大的晶格体积变化,造成二次球三元材料在循环过程中容易发生颗粒破碎,导致电池阻抗增加和衰减严重。而单晶三元材料几乎由一次颗粒构成,循环过程颗粒保持较好。通过将市售的单晶NCM 811和二次球NCM811分别制作成5 Ah软包叠片电池,研究对比发现:二次球NCM811在室温25℃下经过2 000次循环容量保持率为84.2%,而单晶NCM811电芯容量保持率90.5%;在45℃下,二次球样品经过1 300次循环,容量衰减到80%,而单晶样品经过2 000次循环容量保持率仍有86.3%,具有更优的循环性能。其他关键指标,如存储、产气等方面单晶优势明显。 相似文献
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