Reversible potassium storage in ultrafine CF_(x): A superior cathode material for potassium batteries and its mechanism  

作　　者：Hongjun Yue Huixin Chen Chen Zhao Zhiming Zheng Ke Zhou Qjaobao Zhang Guiming Zhong Can-Zhong Lu Yong Yang 

机构地区：[1]CAS Key Laboratory of Design and Assembly of Functional Nanostructures,and Fujian Provincial Key Laboratory of Nanomaterials,Fujian Institute of Research on the Structure of Matter,Chinese Academy of Sciences,Fuzhou 350002,Fujian,China [2]Xiamen Institute of Rare Earth Materials,Haixi Institutes.Chinese Academy of Sciences,Xiamen 361021,Fujian.China [3]College of Chemistry,Fuzhou University.Fuzhou 350108,Fujian,China [4]Department of Materials Science and Engineering,College of Materials,Xiamen University,Xiamen 361005,Fujian,China [5]State Key Lab of Physical Chemistry of Solid Surfaces,Collaborative Innovation Center of Chemistry for Energy Materials and Department of Chemistry,Xiamen University,Xiamen 361005,Fujian,China

出　　处：《Journal of Energy Chemistry》2021年第2期347-353,I0012,共8页能源化学（英文版）

基　　金：financially supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB20000000);the Key Program of Frontier Science, CAS (QYZDJ-SSW-SLH033);the National Natural Science Foundation of China (21603231, 21805278, 21875252 and 21521061);the Leading Project Foundation of Science Department of Fujian Province (2018H0034);the Natural Science Foundation of Fujian Province (2017J05039, 2006L2005);the FJIRSM&IUE Joint Research Fund (No. RHZX-2018-002);FJIRSM Project (CXZX-2017-T04)。

摘　　要：Current studies of cathodes for potassium batteries(PBs) mainly focus on the intercalation-type materials.The conversion-type materials that possess much higher theoretical capacities are rarely discussed in previous literatures.In this work,carbon fluoride(CF_x) is reported as a high capacity conversion-type cathode for PBs for the first time.The material delivers a remarkable discharge capacity of>250 mAh g^(-1) with mid-voltage of 2.6 V at 20 mA g^(-1).Moreover,a highly reversible capacity of around 95 mAh g^(-1) is achieved at 125 mA g^(-1) and maintained for 900 cycles,demonstrating its excellent cycling stability.The mechanism of this highly reversible conversion reaction is further investigated by nuclear magnetic resonance spectra,X-ray diffraction,and transmission electron microscopy studies.According to the analyses,the C-F bond in the cycled material is different from that in the pristine state,which presents relatively higher reversibility.This finding offers important insights for further improving the performance of the CF_x.This work not only demonstrates the CF_x as a high performance cathode for PBs,but also paves a new avenue of exploring conversion-type cathodes for high energy density PBs.

关 键 词：Potassium batteries Carbon fluoride NMR spectroscopy Conversion reaction Cathode 

分 类 号：TM912[电气工程—电力电子与电力传动] TB34[一般工业技术—材料科学与工程]