Shimokawa Kohei, Atsumi Taruto, Okamoto Norihiko L, Kawaguchi Tomoya, Imashuku Susumu, Wagatsuma Kazuaki, Nakayama Masanobu, Kanamura Kiyoshi, Ichitsubo Tetsu
Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan.
Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, 6-3 Aramaki Aza Aoba, Aoba-ku, Sendai, 980-8578, Japan.
Adv Mater. 2021 Feb;33(7):e2007539. doi: 10.1002/adma.202007539. Epub 2021 Jan 18.
Development of metal-anode rechargeable batteries is a challenging issue. Especially, magnesium rechargeable batteries are promising in that Mg metal can be free from dendrite formation upon charging. However, in case of oxide cathode materials, inserted magnesium tends to form MgO-like rocksalt clusters in a parent phase even with another structure, which causes poor cyclability. Here, a design concept of high-performance cathode materials is shown, based on: i) selecting an element to destabilize the rocksalt-type structure and ii) utilizing the defect-spinel-type structure both to avoid the spinel-to-rocksalt reaction and to secure the migration path of Mg cations. This theoretical and experimental work substantiates that a defect-spinel-type ZnMnO meets the above criteria and shows excellent cycle performance exceeding 100 cycles upon Mg insertion/extraction with high potential (≈2.5 V vs Mg /Mg) and capacity (≈100 mAh g ). Thus, this work would provide a design guideline of cathode materials for various multivalent rechargeable batteries.
金属阳极可充电电池的开发是一个具有挑战性的问题。特别是，镁可充电电池很有前景，因为镁金属在充电时不会形成枝晶。然而，对于氧化物阴极材料，即使具有另一种结构，插入的镁也倾向于在母相中形成类似MgO的岩盐簇，这导致循环性能较差。在此，展示了一种高性能阴极材料的设计概念，其基于：i）选择一种使岩盐型结构不稳定的元素，以及ii）利用缺陷尖晶石型结构来避免尖晶石到岩盐的反应并确保镁阳离子的迁移路径。这项理论和实验工作证实，缺陷尖晶石型ZnMnO符合上述标准，并且在高电位（相对于Mg /Mg约为2.5 V）和容量（约100 mAh g）下进行镁插入/脱出时，显示出超过100次循环的优异循环性能。因此，这项工作将为各种多价可充电电池的阴极材料提供设计指导。
