醋酸盐体系无焰燃烧合成LiMnˇ2Oˇ4及性能研究
Preparation and electrochemical properties of LiMnˇ2Oˇ4 prepared by a combustion synthesis in the acetate system
云南民族大学学报:自然科学版,2016,25(1):10-13

刘晓芳 LXF

摘要


以醋酸锂和醋酸锰为原料,浓硝酸为辅助氧化剂,在温度600℃、时间3h下采用无焰燃烧合成尖晶石型LiMnˇ2Oˇ4锂离子电池正极材料,研究了不同浓度硝酸对制备尖晶石型LiMnˇ2Oˇ4的影响.通过XRD和SEM分别研究了产物的物相组成及微观形貌;通过电性能测试研究了产物的比容量变化.实验结果表明,当n(Li)∶n(Mn)=1∶2(mol/mol)时,可得到LiMnˇ2Oˇ4单相,硝酸浓度对燃烧产物颗粒影响也较大;硝酸浓度为15mol/L时产物初始放电比容量为112.1mAh/g,40次充放电循环后,放电比容量为99.0mAh/g,容量保持率为88.3%,具有较好的容量及存储性能.

The spinel LiMnˇ2Oˇ4 cathode materials for rechargeable lithiumion batteries were synthesized by a combustion method at the temperature of 600℃ for 3h, and lithium acetate and manganese acetate were selected as raw materials with concentrated nitric acid as the auxiliary oxidant. The effects of different concentrations of nitric acid on the preparation of LiMnˇ2Oˇ4 were investigated. The phase composition and microtopography of LiMnˇ2Oˇ4 were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The variation of discharge capacity of LiMnˇ2Oˇ4 was studied by the galvanostatic charge-discharge test. The results showed that a single-phase LiMnˇ2Oˇ4 product could be formed when the molar ration of Li to Mn was 1∶2. Meanwhile, the concentration of nitric acid had much influence on the size of the particles. The LiMnˇ2Oˇ4 exhibited a superior capacity retention rate and storage performance when the concentration of nitric acid was 15 mol/L, which delivered a discharge capacity of 112.1mAh/g with a retention of 88.3% after 40 cycles at 0.2 C (148mAh/g).


参考



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