کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1285055 | 973114 | 2010 | 6 صفحه PDF | دانلود رایگان |
The cathode materials Li1−x[Ni0.5Mn1.5]O4 prepared by coprecipitation from acetate solution by oxalic acid and annealing at 900 °C in air had the preferred disordered Ni and Mn on the 16d octahedral sites of a spinel Fd3¯m structure. The coprecipitation method provides better crystallinity than the Fd3¯m phase previously obtained by quenching from the melt. Polycrystalline octahedral-shaped particles with smooth surfaces contained trace amounts of a LiyNi1−yO impurity that introduced some Mn(III) into the spinel phase. Half-cells cycled at 0.2 C rate between 3.5 and 4.8 V versus Li exhibited a flat voltage V ≈ 4.7 V with a small step at x ≈ 0.5 and a capacity at room temperature of 130 mAh g−1 that showed no fade after 50 cycles. A small capacity fade was initiated with a cut-off voltage ≥4.9 V; a significant capacity loss between 2 and 5 C cycling rates was reversible to 134 mAh g−1 on returning to 0.1 C after 50 cycles at 10 C between 3.5 and 5.0 V.
Journal: Journal of Power Sources - Volume 195, Issue 9, 1 May 2010, Pages 2918–2923