高性能LiNi0.8Co0.1Mn0.1O2正极材料的合成及其电化学性能

通过改变煅烧过程中的气氛条件，以简单的固相法合成工艺获得了优异性能的LiNi_0.8Co_0.1Mn_0.1O₂(NCM811)材料，并探究了不同O₂流量对样品的结构和电化学性能的影响。结果表明，当O₂流量为0.1 L/min时，所合成的LiNi_0.8Co_0.1Mn_0.1O₂样品具有最低的阳离子混乱程度和较大的晶面间距。该样品在1 C、4.3 V下循环100次后的放电容量为174 mA·h·g?1，容量保持率高达98.3%；在更高的2 C倍率下循环100次后的保持率也达96.8%，并在高截止电压条件下表现良好。从实验结果还可得出，过低的O₂流量不利于Ni2+转化为Ni3+，从而造成较高的阳离子混排度，而过高的O₂流量则会使所合成LiNi_0.8Co_0.1Mn_0.1O₂材料的晶胞体积减小，不利于Li+的脱嵌。 

Investigations on synthesis and electrochemical performance of high performance LiNi0.8Co0.1Mn0.1O2 cathode material

A facie solid-state route has been employed to synthesize LiNi_0.8Co_0.1Mn_0.1O₂ material with superior electrochemical performance by varying the oxygen flow rate during the calcination process, and the effect of different oxygen flow rates on the structure and electrochemical performance of LiNi_0.8Co_0.1Mn_0.1O₂ has also been investigated. It reveals that the LiNi_0.8Co_0.1Mn_0.1O₂ material synthesized under a flow rate of 0.1 L/min has the lowest degree of cation mixing among all samples and large d-space. The 0.1 L/min sample shows a discharge capacity of 174 mA·h·g?1 after 100 cycles at 1 C, corresponding to the capacity retention rate of 98.3%. A retention rate as high as 96.8% is achieved at 2 C, and good performance is also obtained in high cut-off votage test. Moreover, we confirm that low oxygen-flow rate can lead to high degree of cation mixing because of high content of Ni2+, and high oxygen-flow rate can decrease the d-spacing of LiNi_0.8Co_0.1Mn_0.1O₂ material, thereby being harmful for the Li+ intercalation/deintercalation.