Department of Nanotechnology and Advanced Materials Engineering & Sejong Battery Institute , Sejong University , Seoul 05006 , South Korea.
Department of Energy Engineering , Hanyang University , Seoul 04763 , South Korea.
ACS Appl Mater Interfaces. 2019 Nov 20;11(46):43312-43319. doi: 10.1021/acsami.9b18540. Epub 2019 Nov 7.
Here, we present KMnO·0.15HO, which has a two-dimensional open framework, as an intercalation host for potassium ions. KMnO·0.15HO has a layered structure consisting of edge-sharing MnO octahedra with a large basal spacing of ∼7.3 Å, which facilitates K-ion mobility. Water molecules in the interlayers between the MnO layers play an important role as a pillar to support the structure during repetitive de/potassiation cycles, as confirmed by an operando X-ray diffraction study. As a result, the large K ions readily migrate into the crystal structure, resulting in satisfactory electrochemical performance in K-cells. With the aid of the structural pillar, the KMnO·0.15HO cathode delivers a high reversible capacity of 150 mA h g over 100 cycles at a rate of 0.1 C (15 mA g), with acceptable power capability up to 5 C-rates.
在这里，我们提出了 KMnO·0.15HO，它具有二维开放式框架，可作为钾离子的插层主体。KMnO·0.15HO 具有层状结构，由边缘共享的 MnO 八面体组成，其基底间距约为 7.3 Å，有利于 K 离子的迁移。MnO 层之间的层间水分子作为支柱在重复的脱/嵌钾循环中起到支撑结构的重要作用，这一点通过原位 X 射线衍射研究得到了证实。结果，大的 K 离子容易迁移到晶体结构中，从而在 K 电池中表现出令人满意的电化学性能。在结构支柱的辅助下，KMnO·0.15HO 正极在 0.1 C（15 mA g）的速率下循环 100 次后，可逆容量高达 150 mA h g，在高达 5 C 的倍率下也具有可接受的功率性能。
