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在分层NaNiO₂阴极中减轻排序以提高固体溶液的行为₂

Krishnakanth Sada¹, Steven Kmiec¹, Arumugam Manthiram¹

¹Materials Science and Engineering Program and Texas Materials Institute, The University of Texas at Austin, Austin, Texas, 78712, USA.

Angewandte Chemie (International ed. in English)

|April 16, 2024

概括

在氧化中取代可以提高离子电池的结构稳定性. 这一策略减轻了Jahn-Teller扭曲,并改善了100个周期的容量保留.

科学领域:

材料科学材料科学材料科学
电化学电化学电化学
固态化学固态化学

背景情况:

O型分层氧化物由于Ni3+离子的Jahn-Teller扭曲而表现出结构不稳定性.
这些材料在离子 (Na⁺) 插入/提取过程中经历相变,限制了它们在离子电池中的性能.
稳定结构完整性对于开发高性能离子储能系统至关重要.

研究的目的:

为了研究5%的双价 (Mg2+) 或三价 (Al3+,Co3+) 离子替代O型分层氧化物中的Ni3+的效果.
为了减轻Na的排序和扰乱Jahn-Teller效应以增强结构稳定性.
了解基本的结合相互作用及其对结构和电化学性质的影响.

主要方法:

在氧化结构中的系统性离子替代 (Mg2+,Al3+,Co3+).
对Mg-O和Na-O/Mg-O-Na结合相互作用的分析.
范弗莱克扭曲模式的计算.
使用操作式X射线衍射进行远程结构分析.
短距离结构分析使用神奇角度旋转核磁共振.

主要成果:

替代Mg2+导致Mg-O键的离子性增加,保护氧气免受Na+离子的影响.
计算显示了NiO6八面体从Jahn-Teller扭曲放松,并减少了Mg2+的间层电子密度.
运行X射线衍射和旋转神奇角度的核磁共振揭示了减少排序和稳定的连续固体溶液.
用替代的样本在100个循环后表现出高容量保留率~96%.

结论:

替代有效地减轻了Jahn-Teller扭曲,并改善了O型分层氧化的结构稳定性.
增强的结构完整性导致电化学性能改善和离子电池的高容量保留.
这一战略为开发强大的高性能离子储能材料提供了一个有前途的途径.

关键词:

阴极是天主体,它们是天主体.电化学电化学电化学层层的氧化物层层的氧化物操作的特征描述.离子电池离子电池

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