Intermediate honeycomb ordering to trigger oxygen redox chemistry in layered battery electrode.
Intermediate honeycomb ordering to trigger oxygen redox chemistry in layered battery electrode.
复制标题
DOI：
10.1038/ncomms11397
复制
发表时间：
2016-04-18
影响因子：
16.6
通讯作者：
Yamada A
中科院分区：
文献类型：
--
作者：
Mortemard de Boisse B;Liu G;Ma J;Nishimura SI;Chung SC;Kiuchi H;Harada Y;Kikkawa J;Kobayashi Y;Okubo M;Yamada A
钠离子电池是一种很有吸引力的能量存储介质，因为钠含量丰富，但现有正极材料的低容量使其不切实际。钠过量金属氧化物Na2MO3(M：过渡金属)是一种很有吸引力的正极材料，可以通过额外的氧氧化还原反应实现大容量。然而，提高Na2MO3能力的一般战略制定得很差。在这里，我们使用两种不同晶型的Na2RuO_3，证明了蜂窝状阳离子有序化在Na2Mo3中的关键作用。具有蜂窝状有序[Na1/3Ru2/3]O2平板的有序Na2RuO_3提供了180 mAh g−1(1.3电子反应)的容量，而无序Na_2RuO_3只提供了135 mAh g−1(1.0电子反应)。我们阐明了有序Na2RuO_3的巨大额外容量是由于具有钛铁矿O1结构的自发有序的中间Na1RuO_3相，它诱导了前线轨道重组来触发氧氧化还原反应，揭示了高容量Na2Mo3阴极中稳定的氧氧化还原反应的一般必要条件。钠过量金属氧化物Na2MO3是目前备受关注的钠离子电池正极材料。在这里，作者证明了Na_2RuO_3中的蜂窝状阳离子有序通过前线轨道重组触发了氧氧化还原反应，比无序Na_2RuO_3的容量提高了1/3。
Sodium-ion batteries are attractive energy storage media owing to the abundance of sodium, but the low capacities of available cathode materials make them impractical. Sodium-excess metal oxides Na2MO3 (M: transition metal) are appealing cathode materials that may realize large capacities through additional oxygen redox reaction. However, the general strategies for enhancing the capacity of Na2MO3 are poorly established. Here using two polymorphs of Na2RuO3, we demonstrate the critical role of honeycomb-type cation ordering in Na2MO3. Ordered Na2RuO3 with honeycomb-ordered [Na1/3Ru2/3]O2 slabs delivers a capacity of 180 mAh g−1 (1.3-electron reaction), whereas disordered Na2RuO3 only delivers 135 mAh g−1 (1.0-electron reaction). We clarify that the large extra capacity of ordered Na2RuO3 is enabled by a spontaneously ordered intermediate Na1RuO3 phase with ilmenite O1 structure, which induces frontier orbital reorganization to trigger the oxygen redox reaction, unveiling a general requisite for the stable oxygen redox reaction in high-capacity Na2MO3 cathodes. Sodium-excess metal oxides Na2MO3 are appealing cathode materials for sodium-ion batteries. Here, the authors demonstrate that honeycomb-type cation ordering in Na2RuO3 triggers the oxygen redox reaction via frontier orbital reorganization, increasing the capacity by 1/3 compared with disordered Na2RuO3.