Inhibiting Oxygen Release from Li-rich, Mn-rich Layered Oxides at the Surface with a Solution Processable Oxygen Scavenger Polymer,Advanced Energy Materials

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Inhibiting Oxygen Release from Li-rich, Mn-rich Layered Oxides at the Surface with a Solution Processable Oxygen Scavenger Polymer
Advanced Energy Materials ( IF 24.4 ) Pub Date : 2021-06-27 , DOI: 10.1002/aenm.202100552
Se Young Kim ₁ , Chan Sun Park ₁ , Shahrzad Hosseini ₁ , Jordan Lampert ₂ , Young Jin Kim ₂ , Linda F. Nazar ₁

Affiliation

Li-rich Mn-rich layered oxides (LRLO) are considered promising cathode materials for high energy density storage because of their very high capacities that owe to the reversible redox of oxide anions. However, LRLO cathodes also evolve reactive oxygen species on charge, especially in the first formation cycles, which leads to reactivity with the electrolyte at the surface, reconstruction of surface layers, and deleterious impedance growth. Here, a strategy to enhance the cycle performance of a Li-rich Mn-rich layered cathode is demonstrated by scavenging the evolved oxygen species with a polydopamine (PDA) surface coating. PDA, a well-known oxygen radical scavenger, provides a chemically protective layer that diminishes not only the growth of the undesirable cathode electrolyte interphase but also results in less oxygen gas release compared to an unprotected surface, and significantly suppressed phase transformation at the surface. These factors lead to improved rate capability and diminished capacity fading on cycling; namely a capacity fade of 82% over 200 cycles at a C rate for the PDA-coated LRLO, compared to 70% for the bare LRLO material.

中文翻译：

使用可溶液加工的除氧聚合物抑制表面富锂、富锰层状氧化物的氧释放

富锂锰层状氧化物（LRLO）被认为是用于高能量密度存储的有前途的正极材料，因为它们具有非常高的容量，这归因于氧化物阴离子的可逆氧化还原。然而，LRLO 阴极在充电时也会产生活性氧，特别是在第一次形成循环中，这会导致与表面电解质的反应、表面层的重建和有害的阻抗增长。在这里，通过用聚多巴胺 (PDA) 表面涂层清除析出的氧物种，证明了一种提高富锂富锰层状阴极循环性能的策略。PDA，一种著名的氧自由基清除剂，提供了一个化学保护层，它不仅减少了不需要的阴极电解质中间相的生长，而且与未受保护的表面相比，减少了氧气的释放，并显着抑制了表面的相变。这些因素导致倍率性能的提高和循环时容量衰减的减少；即 PDA 涂层的 LRLO 以 C 速率在 200 次循环中的容量衰减为 82%，而裸露的 LRLO 材料为 70%。

更新日期：2021-08-12

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