Unveiling anomalous lattice shrinkage induced by Pi-backbonding in Prussian blue analogues

作     者：Ju-Hyeon Lee Jin-Gyu Bae Hyeon Jeong Lee Ji Hoon Lee Ju-Hyeon Lee;Jin-Gyu Bae;Hyeon Jeong Lee;Ji Hoon Lee

作者机构：School of Materials Science and EngineeringKyungpook National UniversityDaegu 41566Republic of Korea Department of MaterialsUniversity of OxfordOxford OX13PHUnited Kingdom 

出 版 物：《Journal of Energy Chemistry》 (能源化学（英文版）)

年 卷 期：2022年第31卷第7期

页      面：121-128,I0004页

核心收录：

学科分类：0820[工学-石油与天然气工程] 0808[工学-电气工程] 07[理学] 08[工学] 070304[理学-物理化学(含∶化学物理)] 0817[工学-化学工程与技术] 0703[理学-化学] 

基　　金：supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(Ministry of Science and ICT)(NRF-2021R1G1A1092280 and NRF2019R1A6A3A03031343) the Dongil Culture and Scholarship Foundation the technical support provided at 1-D(KIST-PAL XRD and XAFS)and 7-D beamlines(XAFS)of the Pohang Light Source-II at the Pohang Accelerating Laboratory。 

主　　题：Prussian blue analogues X-ray diffraction X-ray absorption fine structure Pi-backdonation Cyanides 

摘      要：Transition-metal(TM)-based Prussian blue and its analogues(TM-PBAs) have attracted considerable attention as cathode materials owing to their versatile ion storage capability with tunable working voltages. TM-PBAs with different crystal structures, morphologies, and TM combinations can exhibit excellent electrochemical properties because of their unique and robust host frameworks with well-defined ionic diffusion channels. Nonetheless, there is still a lack of understanding regarding the performance dependence of TM-PBAs on structural changes during charging/discharging processes. In this study, in situ X-ray diffraction and X-ray absorption fine structure analyses elucidate the TMdependent structural changes in a series of TM-PBAs during the charging and discharging processes.During the discharging process, the lattice volume of Fe-PBA increased while those of Ni-and Cu-PBAs decreased. This discrepancy is attributed to the extent of size reduction of the cyanometallate complex([Fe(CN)_(6)]) via pi-backbonding from Fe to C due to redox flips of the low-spin Fe^(3+/2+) ion. This study presents a comprehensive understanding of how TM selection affects capacity acquisition and phase transition in TM-PBAs, a promising class of cathode materials.