熔融盐法合成高密度锂离子电池正极材料LiNi0.8Co0.2-xAlxO2

利用低共熔组成的0.38LiOH-0.62LiNO3混合锂盐体系,与高密度前驱体Ni0.8Co0.2-xAlx(OH)2(0≤x≤0.15)在低温下自混合,无需前期研磨和后续洗涤,直接制备出高密度Co-Al共掺杂的锂离子电池正极材料LiNi0.8Co0.2-xAlxO2(0≤x≤0.15)。X射线衍射分析结果表明,合成的LiNi0.8Co0.2-xAlxO2具有规整的层状α-NaFeO2结构。扫描电镜显示产物颗粒均匀,LiNi0.8Co0.15Al0.05O2的振实密度达2.97g·cm-3。电性能测试表明,在0.2C放电倍率和3.0～4.3V的电压范围内,LiNi0.8Co0.15Al0.05O2首次放电比容量达167.5mAh·g-1,且具有良好的循环性能。

Preparation of High-Density LiNi0.8Co0.2-xAlxO2 as Cathode Material for Lithium Ion Battery by Molten Salt Method

Co-Al co-doped cathode material LiNi_(0.8)Co_(0.2-x)Al_xO_2 (0≤x≤0.15) was directly synthesized without artificial grinding and washing by a eutectic molten-salt mixture (0.38LiOH-0.62LiNO_3) method. According to this method, the eutectic molten-salt mixture was self-mixed with high tap density precursor Ni_(0.8)Co_(0.2-x)Al_x(OH)_2 thoroughly at low temperature and then sintered at a certain temperature. The tap-density of LiNi_(0.8)Co_(0.15)Al_(0.05)O_2 obtained is 2.97 g·cm~(-3). According to XRD and SEM, these LiNi_(0.8)Co_(0.2-x)Al_xO_2 materials have an order α-NaFeO_2 layer structure and regular morphology. The charge-discharge tests show that the LiNi_(0.8)Co_(0.15)Al_(0.05)O_2 has an initial discharge capacity as high as 167.5 mAh·g~(-1) and excellent capacity retention in the range from 3.0 V to 4.3 V at a specific current of 0.2 C.