Elucidation of the sodium kinetics in layered P-type oxide cathodes  

作　　者：Lianzheng Yu Haojie Dong Yu-Xin Chang Zhiwei Cheng Kang Xu Yi-Hu Feng Duo Si Xu Zhu Mengting Liu Bing Xiao Peng-Fei Wang Sailong Xu 

机构地区：[1]State Key Laboratory of Chemical Resource Engineering,Beijing University of Chemical Technology,Beijing 100029,China [2]Center of Nanomaterials for Renewable Energy,State Key Laboratory of Electrical Insulation and Power Equipment,School of Electrical Engineering,Xi’an Jiaotong University,Xi’an 710049,China

出　　处：《Science China Chemistry》2022年第10期2005-2014,共10页中国科学（化学英文版）

基　　金：supported by the National Natural Science Foundation of China (U1607128,52102302 and 21521005);Natural Science Foundation of Beijing (2222020);the Young Talent Support Plan and Siyuan Scholar of Xi’an Jiaotong University (DQ6J011 and DQ1J009);State Key Laboratory of Electrical Insulation and Power Equipment (EIPE23313)

摘　　要：Sodium-ion intercalation oxides generally possess high compositional diversity according to their different stacking sequences.The sodium diffusion pathway in layered P-type materials used in sodium-ion batteries is open,which can increase their rate capability by directly transmitting Na+between adjacent triangular prismatic channels,rather than passing through an intermediate tetrahedral site in O-type structure.However,how the structure chemistry of the P-type oxides determines their electrochemical properties has not been fully understood yet.Herein,by comparing the crystalline structures,electrochemical behaviors,ion/electron transport dynamics of a couple of P-type intercalation cathodes,P2-Na_(2/3)Ni1/3Mn_(2/3)O_(2)and P3-Na_(2/3)Ni_(1/3)Mn_(2/3)O_(2)with the same compositions,we demonstrate experimentally and computationally that the P2 phase delivers better cycling stability and rate capability than the P3 counterpart due to the predominant contribution of the faster intrinsic Na diffusion kinetics in the P2 bulk.We also point out that it is the electronic conductivity that captures the key electrochemistry of layered P3-type materials and makes them possible to enhance the sodium storage performance.The results reveal that the correlation between stacking structure and functional properties in two typical layered P-type cathodes,providing new guidelines for preparing and designing alkali-metal layered oxide materials with improved battery performance.

关 键 词：sodium-ion batteries cathode P2 phase P3 phase KINETICS 

分 类 号：TM912[电气工程—电力电子与电力传动] TQ131.12[化学工程—无机化工]