Controllable Heterojunctions with a Semicoherent Phase Boundary Boosting the Potassium Storage of CoSe2/FeSe2

作者：Hui Shan, Jian Qin, Yingchun Ding, Hirbod Maleki Kheimeh Sari, Xuexia Song, Wen Liu, Youchen Hao, Jingjing Wang, Chong Xie, Jiujun Zhang, Xifei Li · 发表于：Advanced Materials · 年份：2021 · DOI：10.1002/adma.202102471 · 被引用次数：229 · 研究领域：Advancements in Battery Materials、Iron-based superconductors research、2D Materials and Applications

Abstract Heterostructure construction is an efficient method for reinforcing K + storage of transition metal selenides. The spontaneously developed internal electric fields give a strong boost to charge transport and significantly reduce the activation energy. Nevertheless, perfection of the interfacial region based on the energy level gradient and lattice matching degree is still a great challenge. Herein, rich vacancies and ultrafine CoSe 2 –FeSe 2 heterojunctions with semicoherent phase boundary are simultaneously obtained, which possess unique electronic structures and abundant active sites. When employed as anodes for potassium‐ion batteries (PIBs), CoSe 2 –FeSe 2 @C composites display a reversible potassium storage of 401.1 mAh g −1 at 100 mA g −1 and even 275 mAh g −1 at 2 A g −1 . Theoretical calculation also reveals that the potassium‐ion diffusion can be dramatically promoted by the controllable CoSe 2 –FeSe 2 heterojunction.