Controlled Dy-doping to nickel-rich cathode materials in high temperature aerosol synthesis
Controlled Dy-doping to nickel-rich cathode materials in high temperature aerosol synthesis
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DOI：
10.1016/j.proci.2020.06.332
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发表时间：
2020-09
影响因子：
4.4
通讯作者：
Chao Yan;Xiaofang Yang;Hao Zhao;Hongtao Zhong;Guoming Ma;Yongfeng Qi;B. Koel;Y. Ju
中科院分区：
文献类型：
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作者：
Chao Yan;Xiaofang Yang;Hao Zhao;Hongtao Zhong;Guoming Ma;Yongfeng Qi;B. Koel;Y. Ju
层状富镍材料具有高容量、低成本等优点，是下一代锂离子电池正极材料的发展方向。然而，热稳定性差和长期循环性能限制了高镍材料的商业应用。杂原子掺杂是提高正极材料电化学性能的有效途径。控制掺杂浓度和几何分布是最佳电化学性能所需的，但这在传统的共沉淀方法中具有挑战性。在这项工作中，控制镝（Dy）掺杂到NCM 811的气溶胶合成方法进行了研究，通过控制前体浓度和加热参数。采用SEM、XRD、XPS对材料进行了表征，并对其电化学性能和热稳定性进行了评价。通过控制掺杂浓度（1.5%），Dy掺杂的NCM 811在长期循环和高倍率性能同时得到改善。在微流反应器中用质谱仪研究了Dy掺杂阴极材料的热化学稳定性。结果表明，Dy掺杂使正极材料的氧起始温度向高温移动，氧释放量降低了80%，从而显著提高了正极材料的热化学稳定性，提高了正极材料的防火安全性。由于高温气溶胶合成是一种低成本和可扩展的方法，因此这项工作的发现对具有受控掺杂改性的新型材料的商业合成具有广泛的影响，以实现锂离子电池的高电化学性能和安全性。
Layered nickel-rich materials are promising next-generation cathode materials for lithium ion batteries due to their high capacity and low cost. However, the poor thermal stability and longtime cycling performance hinders the commercial applications of high nickel materials. Doping with heteroatoms has been an effective approach for improving electrochemical performance of cathode materials. Controlling doping concentration and geometrical distribution is desired for optimal electrochemical performance, but it is challenging in traditional co-precipitation methods. In this work, controlled dysprosium (Dy) doping to NCM811 was studied in an aerosol synthesis method by controlling the precursor concentrations and heating parameters. The obtained materials were characterized by SEM, XRD, and XPS, and their electrochemical properties and thermal stability were evaluated. By controlling the doping concentration (1.5%), Dy-doped NCM811 was improved simultaneously in long-term cycling and high-rate performance. The thermal-chemical stability of the Dy-doped cathode materials was examined in a microflow reactor with a mass spectrometer. The results showed that Dy-doping shifted the O2onset temperature to a higher temperature and reduced O2release by 80%, thus dramatically increasing the thermal-chemical stability and improving the fire safety of cathode materials. Since high temperature aerosol synthesis is a low-cost and scalable method, the findings in this work have broad implications for commercial synthesis of novel materials with controlled doping modification to achieve high electrochemical performance and safety in lithium ion batteries.