Synthesis and Electrochemical Properties of Li(Ni0.5Co0.2Mn0.3)1-2xTixNbxO2
- 2013年第19卷 
采用共沉淀-高温固相烧结法在900 oC空气中煅烧，合成了层状复合掺杂型正极材料Li(Ni0.5Co0.2Mn0.3)1-2xTixNbxO2（x=0，0.002，0.005，0.01，0.02）. 通过扫描电镜（SEM）、X-射线衍射（XRD）和电化学测试等观察与研究掺杂元素对Li(Ni0.5Co0.2Mn0.3)O2的形貌结构和电化学性能的影响. 结果表明，适量Ti、Nb掺入Li(Ni0.5Co0.2Mn0.3)O2，降低了材料的阳离子混排程度，且晶胞参数随着掺杂量的增加而增加. 与未掺杂材料相比，Ti-Nb复合掺杂的样品具有更好的电性能和高温性能. 当x=0.005时，材料的综合性能最好，方型铝壳电池3.0 ~ 4.2 V电位区间首次1C放电比容165.9 mAh.g-1，常温循环100周期容量保持率96.5%，55 oC循环300周期容量保持率为92.6%，80 oC/6 h高温存储后冷却2 h电池厚度膨胀率9.8%.The cathode-active materials of layered Li(Ni0.5Co0.2Mn0.3)1-2xTixNbxO2（x=0, 0.002, 0.005, 0.01, 0.02）composites were synthesized by the thermal treatment of the coprecipitated precursor at 900 oC in air. The effects of Ti-Nb co-dopants on the structural and electrochemical properties of Li(Ni0.5Co0.2Mn0.3)O2 were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical experiments. The results show that the small amounts of Ti-Nb co-dopants in Li(Ni0.5Co0.2Mn0.3)O2significantly decreased the degree of cation mixing in the layered structure. The lattice parameters increased as the doping contents increased. The Ti-Nb co-doped composite materials exhibited better electrical properties and high temperature performance compared to Li(Ni0.5Co0.2Mn0.3)O2. The best overall performance of Li(Ni0.5Co0.2Mn0.3)1-2xTixNbxO2 was achieved with square battery when x=0.005. The initial specific discharge capacity of 165.9 mAh·g-1 under 1C rate in a voltage range of 3.0 ~ 4.2 V was obtained with the capacity retention of 96.5% after 100th cycles at ambient temperature and the capacity retention of 92.6% after 300th cycles at 55 oC. The thickness swelling rate of the square battery was 9.8% when cooling down for two hours after being stored at 80 oC/6 h.