中南大学学报(英文版)
中南大學學報(英文版)
중남대학학보(영문판)
JOURNAL OF CENTRAL SOUTH UNIVERSITY OF TECHNOLOGY(ENGLISH EDITION)
2015年
6期
2036-2042
,共7页
粟劲苍%周广%裴勇%杨振华%王先友
粟勁蒼%週廣%裴勇%楊振華%王先友
속경창%주엄%배용%양진화%왕선우
sodium ion batteries%first principles calculation%cathode material%electronic structure
NaxCoO2 is a commonly used cathode material for sodium ion batteries because of its easy synthesis, high reversible capacity and good cyclability. The structural and electrochemical properties of NaxCoO2 during sodium ion insertion/extraction process are studied based on first principles calculations. The calculation results of crystal structure parameters and average intercalation voltage are in good agreement with experiment data. Through calculation of the geometric structure and charge transfer in charging and discharging processes of NaxCoO2, it is found that the oxygen atom surrounding Co of the CoO6 octahedral screens the coulomb potential produced by sodium vacancy in NaxCoO2, and the charge is removed from the entire Co?O layer instead of the Co atom adjacent to sodium vacancy when sodium ions are extracted from the NaCoO2 lattice. Thus, during the insertion/extraction of sodium ion from NaCoO2, the CoO6 octahedral structure undergoes small lattice distortion, which makes the local structure quite stable and is beneficial to the cycling stability of the material for the application of sodium ion batteries.