Scholarlink

<p>High-nickel layered oxide LiNi<sub><i>x</i></sub>Co<sub><i>y</i></sub>Mn<sub><i>z</i></sub>O<sub>2</sub> (where <i>x</i> + <i>y</i> + <i>z</i> = 1 and <i>x</i> ≥ 0.6) has emerged as a primary focus in research on power battery cathode materials, owing to its high energy density and cost-effectiveness. However, high-nickel cathodes are prone to Li/Ni mixing during synthesis, which can potentially affect the discharge specific capacity, rate, and cycling stability of the battery. In high-nickel cathode materials, the degree of Li/Ni mixing is significantly influenced by the sintering temperature. In this study, we comprehensively investigated sintering temperature to achieve high capacity and cycling stability in LiNi<sub>0.8</sub>Co<sub>0.1</sub>Mn<sub>0.1</sub>O<sub>2</sub> (NCM811) cathode materials. We identified the optimal sintering temperature and investigated the mechanism behind performance degradation caused by over-sintering. This study concludes that the NCM811 cathode material synthesized at 760&#xa0;°C exhibits minimal Li/Ni mixing and demonstrates superior electrochemical performance, with a capacity retention of 89.0% after 100 cycles at 1.0&#xa0;C and a low polarization voltage of 0.045&#xa0;V. A series of chemical and structural characterizations reveal a correlation between over-sintering, Li/Ni mixing and capacity decay. Specifically, the over-sintering temperature during synthesis of the NCM811 cathode material exhibits a linear positive correlation with Li/Ni mixing, leading to structural degradation that impedes lithium-ion diffusion pathways. Increased surface reactivity contributes to the formation of unstable cathode–electrolyte interfaces, while elevated interfacial reaction by-products deplete active material, resulting in higher capacity loss. Additionally, the pronounced, steeper two-phase irreversible H2 → H3 phase transition triggered by over-sintering accelerates the layered structure degradation, leading to the rapid decay of capacity.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Effect of sintering temperature on Li/Ni mixing and electrochemical performance in high-nickel LiNi0.8Co0.1Mn0.1O2 cathodes

  • 期刊论文

  • 发表日期：

    2025年3月31日

查看全文
  • Zhiwei Yang,
  • Xianfa Rao,
  • Pan Yang,
  • Xinxiong Zeng,
  • Jingjing Xiong,
  • Tianyong Mao,
  • Shengwen Zhong

摘要

High-nickel layered oxide LiNixCoyMnzO2 (where x + y + z = 1 and x ≥ 0.6) has emerged as a primary focus in research on power battery cathode materials, owing to its high energy density and cost-effectiveness. However, high-nickel cathodes are prone to Li/Ni mixing during synthesis, which can potentially affect the discharge specific capacity, rate, and cycling stability of the battery. In high-nickel cathode materials, the degree of Li/Ni mixing is significantly influenced by the sintering temperature. In this study, we comprehensively investigated sintering temperature to achieve high capacity and cycling stability in LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode materials. We identified the optimal sintering temperature and investigated the mechanism behind performance degradation caused by over-sintering. This study concludes that the NCM811 cathode material synthesized at 760 °C exhibits minimal Li/Ni mixing and demonstrates superior electrochemical performance, with a capacity retention of 89.0% after 100 cycles at 1.0 C and a low polarization voltage of 0.045 V. A series of chemical and structural characterizations reveal a correlation between over-sintering, Li/Ni mixing and capacity decay. Specifically, the over-sintering temperature during synthesis of the NCM811 cathode material exhibits a linear positive correlation with Li/Ni mixing, leading to structural degradation that impedes lithium-ion diffusion pathways. Increased surface reactivity contributes to the formation of unstable cathode–electrolyte interfaces, while elevated interfacial reaction by-products deplete active material, resulting in higher capacity loss. Additionally, the pronounced, steeper two-phase irreversible H2 → H3 phase transition triggered by over-sintering accelerates the layered structure degradation, leading to the rapid decay of capacity.