Yang Su Hyun, Park Seung-Keun, Park Gi Dae, Lee Jong-Heun, Kang Yun Chan
Department of Materials Science and Engineering, Korea University, Anam-Dong, Seongbuk-Gu, Seoul, 136-713, Republic of Korea.
Department of Chemical Engineering, Kongju National University, 1223-24 Cheonan-daero, Seobuk-gu, Cheonan, 31080, Republic of Korea.
Small. 2020 Aug;16(33):e2002345. doi: 10.1002/smll.202002345. Epub 2020 Jul 19.
Potassium-ion batteries (KIBs) are considered as promising alternatives to lithium-ion batteries owing to the abundance and affordability of potassium. However, the development of suitable electrode materials that can stably store large-sized K ions remains a challenge. This study proposes a facile impregnation method for synthesizing ultrafine cobalt-iron bimetallic selenides embedded in hollow mesoporous carbon nanospheres (HMCSs) as superior anodes for KIBs. This involves loading metal precursors into HMCS templates using a repeated "drop and drying" process followed by selenization at various temperatures, facilitating not only the preparation of bimetallic selenide/carbon composites but also controlling their structures. HMCSs serve as structural skeletons, conductive templates, and vehicles to restrain the overgrowth of bimetallic selenide particles during thermal treatment. Various analysis strategies are employed to investigate the charge-discharge mechanism of the new bimetallic selenide anodes. This unique-structured composite exhibits a high discharge capacity (485 mA h g at 0.1 A g after 200 cycles) and enhanced rate capability (272 mA h g at 2.0 A g ) as a promising anode material for KIBs. Furthermore, the electrochemical properties of various nanostructures, from hollow to frog egg-like structures, obtained by adjusting the selenization temperature, are compared.
钾离子电池（KIBs）因其钾资源丰富且价格低廉，被认为是锂离子电池颇具前景的替代品。然而，开发能够稳定存储大尺寸钾离子的合适电极材料仍然是一项挑战。本研究提出了一种简便的浸渍方法，用于合成嵌入中空介孔碳纳米球（HMCSs）中的超细钴铁双金属硒化物，作为钾离子电池的优质阳极。这包括通过重复的“滴加和干燥”过程将金属前驱体负载到HMCS模板中，然后在不同温度下进行硒化，这不仅有助于制备双金属硒化物/碳复合材料，还能控制其结构。HMCSs作为结构骨架、导电模板和载体，可抑制热处理过程中双金属硒化物颗粒的过度生长。采用各种分析策略来研究新型双金属硒化物阳极的充放电机制。这种独特结构的复合材料作为一种有前景的钾离子电池阳极材料，表现出高放电容量（200次循环后在0.1 A g下为485 mA h g）和增强的倍率性能（在2.0 A g下为272 mA h g）。此外，还比较了通过调节硒化温度获得的从空心到蛙卵状结构等各种纳米结构的电化学性能。
