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 

机构地区：[1]School of Materials Science and Engineering,Kyungpook National University,Daegu 41566,Republic of Korea [2]Department of Materials,University of Oxford,Oxford OX13PH,United Kingdom

出　　处：《Journal of Energy Chemistry》2022年第7期121-128,I0004,共9页能源化学（英文版）

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。

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<100> 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.

关 键 词：Prussian blue analogues X-ray diffraction X-ray absorption fine structure Pi-backdonation CYANIDES 

分 类 号：O641.4[理学—物理化学] TM912[理学—化学]