铝掺杂对Li1.2Ni0.2Mn0.6O2结构和电化学性能的影响

摘要

采用共沉淀法合成了球型前驱体Ni0.25Mn0.75 (OH)2,与锂源混合煅烧得到锂离子电池正极材料Li1.2Ni0.2Mn0.6O2,并对其进行铝掺杂改性,得到样品Li1.2(Ni0.2Mn0.6)1-xAl0.8xO2(x=0～0.03).利用X射线衍射(XRD)、扫描电镜(SEM)和电化学性能测试对各个样品的结构、形貌和电化学性能进行了表征,结果表明:掺杂铝后,样品具有规则的球形形貌,层状结构保持完整,阳离子混排程度降低,铝掺杂量为2％的样品(x=O.02)阳离子混排程度最小,结构最稳定,具有较高的首次充放电效率和最优异的循环性能,其首次充放电效率为84.2％,1C倍率下循环50次的容量保持率为95.7％.%The sphere prescursor Ni0.25Mn0.75 (OH)2 was obtained by chemical co-precipitation reaction.The lithium-ion battery cathode material Li1.2Mn0.6Ni0.2O2 was synthesized by mixing and calcining Ni0.25Mn0.75 (OH)2 and lithium source,and then the A1 was doped on Li1.2Ni0.2Mn0.6O2 to obtain the samples Li1.2(Ni02Mn0.6)1-xAl0.8xO2(x=0～0.03).Their structure,morphology,and electrochemical properties were characterized by X-ray diffraction (XRD),scanning electron microscopy (SEM),and electrochemical performance tests.Results showed that the Al-doped samples had regular spherical morphology,a perfect layered structure,and a lower cation mixing degree.The sample with 2％ A1 doping (x =2) had the lowest cation mixing degree,the most stable structure,higher charge-discharge efficiency for the first time,and the most excellent circulation performance,the initial charge and discharge efficiency was 84.2％ at 1C rates,and the capacity retention rate was 95.7％ after cycled 50 times at 1C rates.