LiNi0.5Mn1.5O4 was synthesized by combustion synthesis （UCS） using urea as fuel. X-ray diffraction and scanning electron microscope measurements showed that the spinel structure LiNio.sMnl.504 with the space group F...LiNi0.5Mn1.5O4 was synthesized by combustion synthesis （UCS） using urea as fuel. X-ray diffraction and scanning electron microscope measurements showed that the spinel structure LiNio.sMnl.504 with the space group Fd3m was formed during urea combustion. Both structure and particle size could be adjusted by the amount of urea and the heat treatment temperature used in the UCS. For the LiNi0.5Mn1.5O4 sample prepared with a urea/Li molar ratio of 0.57 and a heat treatment temperature of 900℃, the particle-size distribution fell in a narrow range of 1-2 Dm. Electrochemical tests indicated that this LiNi0.sMnl.504 sample delivered a discharge capacity of 133.6 mAh/g with a capacity retention rate of 99.6% after 20 cycles at 0.5 C.展开更多
LiNi0.5Mn1.504 prepared by a spray drying method was re-treated in N2 at 500, 600 and 700℃, respec- tively. Their structural and electrochemical properties were studied by means of Fourier transform infrared（FTIR）,...LiNi0.5Mn1.504 prepared by a spray drying method was re-treated in N2 at 500, 600 and 700℃, respec- tively. Their structural and electrochemical properties were studied by means of Fourier transform infrared（FTIR）, X-ray diffraction（XRD）, and charge-discharge tests. The space group of the LiNi0.sMnl.504 transforms from P4332 to Fd3m at an annealing temperature of 700℃. The electrochemical characteristics of the treated samples are closely related to the annealing temperature. The sample treated in N2 at 500℃ shows both an improved rate capability and cyclic performance at a high temperature compared with the as-prepared sample, while the sample treated in N2 at 700℃ shows dramatically decrease in its reversible capacity.展开更多
基金the financial support of the Natural Science Foundation of Guangxi,China (No. 0731010,2011GXNSFA018015)the Cooperative Network of Large-scale Instrument of Guangxi,China (No. 701-2008-114)
文摘LiNi0.5Mn1.5O4 was synthesized by combustion synthesis （UCS） using urea as fuel. X-ray diffraction and scanning electron microscope measurements showed that the spinel structure LiNio.sMnl.504 with the space group Fd3m was formed during urea combustion. Both structure and particle size could be adjusted by the amount of urea and the heat treatment temperature used in the UCS. For the LiNi0.5Mn1.5O4 sample prepared with a urea/Li molar ratio of 0.57 and a heat treatment temperature of 900℃, the particle-size distribution fell in a narrow range of 1-2 Dm. Electrochemical tests indicated that this LiNi0.sMnl.504 sample delivered a discharge capacity of 133.6 mAh/g with a capacity retention rate of 99.6% after 20 cycles at 0.5 C.
文摘LiNi0.5Mn1.504 prepared by a spray drying method was re-treated in N2 at 500, 600 and 700℃, respec- tively. Their structural and electrochemical properties were studied by means of Fourier transform infrared（FTIR）, X-ray diffraction（XRD）, and charge-discharge tests. The space group of the LiNi0.sMnl.504 transforms from P4332 to Fd3m at an annealing temperature of 700℃. The electrochemical characteristics of the treated samples are closely related to the annealing temperature. The sample treated in N2 at 500℃ shows both an improved rate capability and cyclic performance at a high temperature compared with the as-prepared sample, while the sample treated in N2 at 700℃ shows dramatically decrease in its reversible capacity.
