改进方法合成钛掺杂锂离子电池三元正极材料

Improved Method to Synthesize Titanium-doped Lithium Ion Battery Ternary Cathode Materials

采用改进溶胶-凝胶法合成了具有良好的晶体结构和电化学稳定性的正极材料Li[Ni_(1/3)Co_(1/3)Mn_(1/3)]_(0.9)Ti_(0.1)O_(2),通过优化前驱体的制备来提高原子混合程度,从而达到改善材料循环稳定性的目的。XRD测试表明,样品的Li^(+)/Ni^(2+)混排程度很低,TEM图片显示材料的结晶度很高,原子排列有序,这有利于实现更大的锂离子扩散系数。在0.5 C倍率下循环200次后,材料的容量保持率高达84.6%,与未掺钛的LiNi_(1/3)Co_(1/3)Mn_(1/3)O_(2)仅为52.0%相比,钛掺杂的材料表现出优异的电化学性能。此外,掺钛材料在0.1、0.2、0.5、1.0、2.0和5.0 C时具有更好的充放电倍率性能,分别为164.9、162.4、152.4、142.4、129.7和102.8 mAh/g。研究成果可以为设计具有更好电化学性能的锂离子电池材料提供参考。

The cathode material Li[Ni_(1/3)Co_(1/3)Mn_(1/3)]_(0.9)Ti_(0.1)O_(2),which has good crystal structure and electrochemical stability,was synthesized by sol-gel method.The degree of atomic mixing was improved by optimizing the preparation of precursors,so as to achieve the purpose of improving the cyclic stability of materials.The XRD test of the material shows that Li^(+)/Ni^(2+)mixing degree of the sample is very low,and the TEM image shows that the material has a high degree of crystallinity and an orderly arrangement of atoms,which is beneficial to achieve a larger lithium ion diffusion coefficient.After 200 cycles at a rate of 0.5 C,the capacity retention rate of the material is as high as 84.6%.Compared with undoped LiNi_(1/3)Co_(1/3)Mn_(1/3)O_(2),which is only 52.0%,the titanium-doped material exhibits excellent electrochemical performance.In addition,the titanium-doped material has better charge-discharge rate performance at 0.1,0.2,0.5,1.0,2.0 and 5.0 C,which is 164.9,162.4,152.4,142.4,129.7 and 102.8 mAh/g.The results of this research could provide reference to design lithium-ion battery materials with better electrochemical performance.