Regulating Built-in Polar States via Atomic Self-Hybridization for Fast Ion Diffusion Kinetics in Potassium Ion Batteries  

作　　者：Hongwei Du Xiaoyun Zhou Tao Li Wen Zhao Dan Zhou Dawei Yang Tianli Wu Ying Xu 

机构地区：[1]Henan Key Laboratory of Quantum Materials and Quantum Energy,School of Future Technology,Henan University,Kaifeng,Henan,475004 China [2]School of Materials and Energy,Lanzhou University,Lanzhou,Gansu,730000 China [3]Department of Materials Science and Engineering,University of Connecticut,Storrs,Connecticut,06269 United States

出　　处：《Chinese Journal of Chemistry》2024年第21期2589-2598,共10页中国化学（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(52001151 and 22305106);Postdoctoral Fellowship Program of CPSF(GZC20230682);Natural Science Foundation of Henan Province(202300410068);Fujian Province(2022J05104);the Science and Technology Foundation for Youths of Gansu Province(21JR7RA518 and 23JRRA1111).

摘　　要：Potassium ion batteries(PIBs)are of great interest owing to the low cost and abundance of potassium resources,while the sluggish diffusion kinetics of K^(+)in the electrode materials severely impede their practical applications.Here,self-hybridized BiOCl_(0.5)Br_(0.5) with a floral structure is assembled and used as anode for PIBs.Based on the systematic theoretical calculation and experimental analysis,the unbalance of charge distribution between Cl and Br atoms leads to an enhanced built-in electric field and a larger interlayer spacing,which can enhance the K^(+)diffusion.Furthermore,the K^(+)insertion causes the energetic evolution of polar states in the BiOCl_(0.5)Br_(0.5) crystal framework,where the dynamic correlation between the K^(+)and the halogen atoms leads to the formation of hole-like polarons,which significantly improves the K^(+)diffusion and reaction kinetics during the charging/discharging process,giving important implications to design the electrode materials with high electrochemical performance by engineering the interaction between electronic structure and interface.Therefore,the BiOCl_(0.5)Br_(0.5) anode obtains an excellent performance of 171 mAh·g^(-1) at 1 A·g^(-1) over 2000 cycles in PIBs.

关 键 词：Bismuth oxyhalide Self-hybridized structure Potassium-ion battery Polar states Density functional theory 

分 类 号：TM912[电气工程—电力电子与电力传动]