醋酸盐体系无焰燃烧合成LiMn_2O_4及性能研究

Preparation and electrochemical properties of LiMn_2O_4 prepared by a combustion synthesis in the acetate system

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3 h下采用无焰燃烧合成尖晶石型Li Mn2O4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Li Mn2O4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Li Mn2O4单相,硝酸浓度对燃烧产物颗粒影响也较大;硝酸浓度为15 mol/L时产物初始放电比容量为112.1 m Ah/g,40次充放电循环后,放电比容量为99.0 m Ah/g,容量保持率为88.3%,具有较好的容量及存储性能.

The spinel LiMn2O4 cathode materials for rechargeable lithium-ion batteries were synthesized by a com- bustion method at the temperature of 600℃ for 3 h, 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 LiMn2O4 were investigated. The phase composition and microtopography of LiMn2O4 were in- vestigated by X -ray diffraction （XRD） and scanning electron microscopy （SEM）, respectively. The variation of discharge capacity of LiMn2O4 was studied by the galvanostatic charge - discharge test. The results showed that a single- phase LiMn2O4 product could be formed when the molar ration of Li to Mn was 1：2. Meanwhile, the con- centration of nitric acid had much influence on the size of the particles. The LiMn2O4 exhibited a superior capacity retention rate and storage performance when the concentration of nitric acid was 15 moL/L, which delivered a dis- charge capacity of 112. 1 mAh/g with a retention of 88.3% after 40 cycles at 0. 2 C （ 148 mAh/g）.