摘要
采用共沉淀-高温固相烧结法在900oC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%,55oC循环300周期容量保持率为92.6%,80oC/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 ℃ 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）O2 significantly 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-xTixNbxO2 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 ℃. The thickness swelling rate of the square battery was 9.8% when cooling down for two hours after being stored at 80 ℃/6 h.
出处
《电化学》
CAS
CSCD
北大核心
2013年第4期371-375,共5页
Journal of Electrochemistry
