锂离子电池高镍正极材料掺铝的作用及掺铝方法的研究

doi:10.13208/j.electrochem.180328

摘要/Abstract

摘要： 为了探究铝对高镍层状氧化物在结构、形貌及性能方面的影响，本文采用两种不同的方式掺铝以制备NCA正极材料（LiNi_0.8Co_0.15Al_0.05O₂）：一是固相法即将共沉淀合成的NC前驱体（Ni_0.84Co_0.16(OH)₂）在混锂烧结过程混入铝源（纳米Al₂O₃或Al(NO₃)₃）；二是共沉淀法即直接在合成前驱体过程中混入铝源（Al₂(SO₄)₃或NaAlO₂）即合成NCA前驱体（Ni_0.8Co_0.15Al_0.05(OH)_2.05）后再混锂烧结. 结果表明，掺铝能够降低阳离子混排程度、维持层状结构的稳定性，改善材料在充放电循环过程的放电电压及中值电压大幅下降的情况，提高其循环性能. 其中以NaAlO₂为铝源合成NCA前驱体所制备的NCA材料性能最优：在3.0 ~ 4.3 V充放电区间，0.1C倍率下首圈放电比容量达198 mAh·g^-1，首次库仑效率可达94.6%，1C倍率下循环200圈后容量保持率达70%.

关键词: 锂离子电池, 共沉淀法, 高镍材料, 铝掺杂

Abstract: In order to investigate the effects of Al-doping on the structure, morphology and electrochemical performance of Ni-rich layered oxides, the NCA cathode materials with a nominal chemical formula of LiNi_0.8Co_0.15Al_0.05O₂ were prepared by two methods with different aluminum sources. One was the solid phase method: the precursor (Ni_0.84Co_0.16(OH)₂) prepared by co-precipitation was mixed with lithium and aluminum source (nano-Al₂O₃ or Al(NO₃)₃) thoroughly, and calcined at 780 ℃ for 15 h under an oxygen atmosphere. The other was the co-precipitation method: the NCA precursor (Ni_0.8Co_0.15Al_0.05(OH)_2.05) was synthesized by co-pre- cipitation method employing either Al₂(SO₄)₃ or NaAlO₂ as an aluminum source, and the NCA precursor was then mixed with lithium source and sintered at 780 ℃ for 15 h under an oxygen atmosphere. The results showed that Al-doping reduced the degree of cation mixing and maintained the stability of the layered structure, thereby reducing the voltage drop and improving its cycle performance. The NCA material prepared by co-precipitation method employing NaAlO₂ as the aluminum source revealed the morphology of dense microspheres with a uniform size distribution and a well-layered structure of low Ni²⁺/Li⁺ mixing, acheving the best performance. The as-prepared NCA cathode material delivered a high discharge capacity (198 mAh·g^-1 at 0.1C) corresponding to 94.6% coulombic efficiency and good cycle stability (a capacity retention of 70% after 200 cycles at 1C) between 3.0 V and 4.3 V.

Key words: Lithium-ion battery, co-precipitation method, Ni-rich cathode; LiNi_0.8Co_0.15Al_0.05O₂, doping

中图分类号:

O646

王丹凤, 李益孝, 王伟立, 杨勇. 锂离子电池高镍正极材料掺铝的作用及掺铝方法的研究[J]. 电化学（中英文）, 2019, 25(6): 660-668.

WANG Dan-feng, LI Yi-xiao, WANG Wei-li, YANG Yong. Effects of Al-Doping on Properties of Ni-Rich Cathode Materials Employing Different Aluminum Sources[J]. Journal of Electrochemistry, 2019, 25(6): 660-668.

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