Vacancy‐Enabled O3 Phase Stabilization for Manganese‐Rich Layered Sodium Cathodes
Vacancy‐Enabled O3 Phase Stabilization for Manganese‐Rich Layered Sodium Cathodes
复制标题
空位 - 使锰 - 富层状钠阴极具有 O3 相稳定性
DOI：
10.1002/anie.202016334
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发表时间：
2021
期刊：
影响因子：
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通讯作者：
Amine, Khalil
中科院分区：
文献类型：
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作者：
Xiao, Biwei;Wang, Yichao;Tan, Sha;Song, Miao;Li, Xiang;Zhang, Yuxin;Lin, Feng;Han, Kee Sung;Omenya, Fredrick;Amine, Khalil
富锰层状氧化物材料作为低成本、高容量的钠离子电池阴极具有巨大的潜力。然而，它们通常形成P2阶段，并且承受快速的容量衰减。在这项工作中，利用过渡金属（TM）和氧空位的产生以及Na和Li的电化学交换，从富含Li和Mn的层状材料中开发出了O3相钠阴极。富锰层状阴极材料在盐化/脱盐过程中主要保持O3相，具有约220 mAh g−1的完全盐化容量。它在2-3.8 V之间提供约160 mAh的g−1比容量，超过250个循环保持> 86%。在去钠化和钠化过程中，预形成的TM和氧空位使得TM从TM层可逆迁移到Na层的四面体位置。迁移会产生亚稳态，导致阻碍O3 - P3完全相变的动能垒增加。
Manganese‐rich layered oxide materials hold great potential as low‐cost and high‐capacity cathodes for Na‐ion batteries. However, they usually form a P2 phase and suffer from fast capacity fade. In this work, an O3 phase sodium cathode has been developed out of a Li and Mn‐rich layered material by leveraging the creation of transition metal (TM) and oxygen vacancies and the electrochemical exchange of Na and Li. The Mn‐rich layered cathode material remains primarily O3 phase during sodiation/desodiation and can have a full sodiation capacity of ca. 220 mAh g−1. It delivers ca. 160 mAh g−1specific capacity between 2–3.8 V with >86 % retention over 250 cycles. The TM and oxygen vacancies pre‐formed in the sodiated material enables a reversible migration of TMs from the TM layer to the tetrahedral sites in the Na layer upon de‐sodiation and sodiation. The migration creates metastable states, leading to increased kinetic barrier that prohibits a complete O3‐P3 phase transition.