锂离子电池镍钴锰正极材料的制备及改性研究
发布时间：2018-09-08 06:47
【摘要】：随着科学技术的迅猛发展,锂离子电池作为目前性能优异的储能方式之一,应用范围是越来越广。在汽车行业应用锂离子电池是目前阶段锂离子电池发展的一个主要方向。这就要求锂离子电池在能量密度,倍率性能和循环稳定性都较好的情况下,同时具备成本低、安全性能好和与环境友好等优点。然而,能满足这些要求的锂离子电池正极材料较少。最近,人们提出了一种具有层状-层状-尖晶石结构的正极材料,得到较好的比容量和循环性能。为了进一步改善电化学性能,又对该材料进行了掺杂和包覆两种改性。在本课题中,采用两步温度共沉淀法制备层状-层状-尖晶石固溶体正极材料δ[0.5Li2Mn O3·0.5Li Mn1/3Ni1/3Co1/3O2]·(1-δ)Li0.5Mn4/6Ni1/6Co1/6O2(也可以简写成Lix Mn4/6Ni1/6Co1/6Oy),并以此为基础对该系材料进行掺杂和包覆改性以求提升其电化学性能。实验结果确定T1=40℃,T2=80℃是两步温度共沉淀法制备正极材料较佳的一个工艺参数。掺杂改性实验选择Li1.1Mn4/6Ni1/6Co1/6O2.30和Li1.2Mn4/6Ni1/6Co1/6O2.35材料进行F-掺杂改性,对比后性能得出掺杂量为0.05为最佳。Li1.1Mn4/6Ni1/6Co1/6O2.25F0.05和Li1.2Mn4/6Ni1/6Co1/6O2.30F0.05材料较未改性材料在0.5 C倍率循环50次的容量保持率提高了8%左右;5 C倍率下的放电比容量与未改性前的材料相比有10~20 m A·h/g幅度的提高。对所制备出的正极材料Li1.1Mn4/6Ni1/6Co1/6O2.30、Li1.2Mn4/6Ni1/6Co1/6O2.35和Li1.3Mn4/6Ni1/6Co1/6O2.40进行Al F3改性,Al F3的包覆量为1 wt%、2 wt%和3 wt%。包覆改性后材料的电化学性能有所改善,但是2 wt%的包覆效果更好;在0.5 C倍率下经过循环50次后,材料的容量保持率提高10%左右;倍率性能也得到了改性,提高幅度在20 m A·h/g左右。
[Abstract]:With the rapid development of science and technology, lithium-ion batteries are widely used as one of the excellent energy storage methods. The application of lithium ion battery in automobile industry is one of the main directions in the development of lithium ion battery at present. This requires that lithium-ion batteries have the advantages of low cost, good safety and environmental friendliness under the condition of good energy density, rate performance and cycle stability. However, there are fewer cathode materials for lithium ion batteries to meet these requirements. Recently, a kind of layered spinel structure cathode material has been proposed to obtain better specific capacity and cycling performance. In order to further improve the electrochemical performance, the material was modified by doping and coating. In this paper, the layered spinel cathode material 未 [0.5Li2Mn O3 0.5Li Mn1/3Ni1/3Co1/3O2] (1- 未) Li0.5Mn4/6Ni1/6Co1/6O2 (also can be abbreviated as Lix Mn4/6Ni1/6Co1/6Oy) was prepared by two-step temperature co-precipitation method. The experimental results show that 40 鈩，
本文编号：2229692
[Abstract]:With the rapid development of science and technology, lithium-ion batteries are widely used as one of the excellent energy storage methods. The application of lithium ion battery in automobile industry is one of the main directions in the development of lithium ion battery at present. This requires that lithium-ion batteries have the advantages of low cost, good safety and environmental friendliness under the condition of good energy density, rate performance and cycle stability. However, there are fewer cathode materials for lithium ion batteries to meet these requirements. Recently, a kind of layered spinel structure cathode material has been proposed to obtain better specific capacity and cycling performance. In order to further improve the electrochemical performance, the material was modified by doping and coating. In this paper, the layered spinel cathode material 未 [0.5Li2Mn O3 0.5Li Mn1/3Ni1/3Co1/3O2] (1- 未) Li0.5Mn4/6Ni1/6Co1/6O2 (also can be abbreviated as Lix Mn4/6Ni1/6Co1/6Oy) was prepared by two-step temperature co-precipitation method. The experimental results show that 40 鈩，
本文编号：2229692
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