Layered Potassium Vanadate K0.5V2O5 as a Cathode Material for Nonaqueous Potassium Ion Batteries
Layered Potassium Vanadate K0.5V2O5 as a Cathode Material for Nonaqueous Potassium Ion Batteries
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层状钒酸钾K0.5V2O5作为非水钾离子电池正极材料
DOI：
10.1002/adfm.201800670
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发表时间：
2018-12-05
影响因子：
19
通讯作者：
Guo, Lin
中科院分区：
文献类型：
--
作者：
Deng, Leqing;Niu, Xiaogang;Guo, Lin
非水钾离子电池（KIBs）是一种新兴的电化学储能技术，由于钾资源丰富，但大尺寸钾离子嵌入电极材料的困难阻碍了KIBs的发展。在这里，层状钒酸钾K0.5V2O5被提议作为KIB的潜在阴极材料。尽管K离子的尺寸很大，但所制造的材料能够在1.5-3.8 V（vs K+/K）的电压范围内在10 mA g（-1）下提供约90 mAh g（-1）的可逆容量，在200 mA g（-1）时，容量为60 mAh g（-1），循环稳定性为81%。在100 mA g（-1）下250次循环后的容量保持率。非原位X射线衍射和X射线光电子能谱表明，层状钒酸钾在钾化/脱钾过程中表现出高度稳定和可逆的结构变化，并在V4+和V5+之间发生跃迁。此外，恒电流间歇滴定技术的结果表明，钾化/脱钾的动力学主要取决于K-离子在活性材料中的扩散。本研究为钒酸钾及其他层状过渡金属氧化物在KIB领域的应用开辟了新的途径。
Nonaqueous potassium ion batteries (KIBs) are one of the emerging electrochemical energy storage technologies due to the abundance of potassium resources, but the difficulties of intercalation of large size K-ions into electrode materials hinder the development of KIBs. Here, a layered potassium vanadate K0.5V2O5 is proposed as a potential cathode material for KIBs. Despite the large size of K-ions, the as-fabricated material is capable of delivering a reversible capacity around 90 mAh g(-1) at 10 mA g(-1) in the voltage range of 1.5-3.8 V (vs K+/K), and also exhibits a fast rate capability with a capacity of 60 mAh g(-1) at 200 mA g(-1) and good cycling stability with 81% capacity retention after 250 cycles at 100 mA g(-1). Ex situ X-ray diffraction and X-ray photoelectron spectroscopy reveal that the layered potassium vanadate exhibits a highly stable and reversible structure change with a transition between V4+ and V5+ upon potassiation/depotassiation. Additionally, galvanostatic intermittent titration technique results show that the kinetics of potassiation/depotassiation is mainly determined by K-ion diffusion in the active material. The present study may open up further exploration of potassium vanadates and other layered transition metal oxides in the field of KIBs.