Magara Kazushi, Hosaka Tomooki, Tatara Ryoichi, Komaba Shinichi
Department of Applied Chemistry, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku, Tokyo 162-8601, Japan.
ACS Appl Mater Interfaces. 2025 May 21;17(20):29610-29618. doi: 10.1021/acsami.5c02298. Epub 2025 May 7.
Potassium vanadium fluorides of KVF, KVF, and KVF have been investigated as potential positive electrode materials for potassium-ion batteries. KVF and KVF exhibit low electrochemical activity with an ∼50 mAh g initial capacity. By contrast, KVF exhibits a promising electrochemical performance, displaying a voltage plateau at 3.7 V and a large initial capacity of 95 mA h g. A reversible V one-electron process is evidenced by X-ray absorption spectroscopy, whereas oxidation from V to V (from KVF to KVF) is mainly irreversible and V (from KVF to KVF) is almost inactive. KVF displays partially irreversible structural changes during potassium extraction/insertion, especially when more than 1 mol of potassium ions are extracted from KVF. These results suggest that structural stability after potassium extraction is a key factor in the design of high-capacity fluoride materials.
已对KVF、KVF和KVF的钾钒氟化物作为钾离子电池的潜在正极材料进行了研究。KVF和KVF表现出低电化学活性，初始容量约为50 mAh g。相比之下，KVF表现出有前景的电化学性能，在3.7 V处显示出电压平台，初始容量为95 mA h g。X射线吸收光谱证明了V的可逆单电子过程，而从V到V（从KVF到KVF）的氧化主要是不可逆的，并且V（从KVF到KVF）几乎没有活性。KVF在钾脱嵌过程中表现出部分不可逆的结构变化，特别是当从KVF中脱出超过1 mol钾离子时。这些结果表明，钾脱出后的结构稳定性是设计高容量氟化物材料的关键因素。
