image: The Na+ migration energy barrier in P2-NaNM is calculated to be 130 meV, which is much lower than that in P3-NaNM (267 meV). view more
Credit: ©Science China Press
A couple of P2 and P3 isomers having the same Na2/3Ni1/3Mn2/3O2 composition and different layered structure were successfully prepared, aiming to reveal the relationship between the crystalline structure and electrochemical properties in P-type cathode materials. Electrochemical testing results manifest that P2-NaNM exhibits better rate performance and cycling stability than those of P3 counterpart. Further experimental analysis combined with density functional theory calculations demonstrates that P2-NaNM phase possesses better bulk sodium diffusion kinetics and lower Na+ diffusion energy barrier, contributing to its excellent electrochemical performance. Meanwhile, the low electronic conductivity of the P3 phase is an important factor determining its rate performance, which lights a path toward enhancing the electrochemical properties of P3 phase by reasonable surface carbon coating. This work highlights the significance of structure–performance relationship in layered P-type oxides and also grasps new insight into designing advanced materials for SIBs.
This study is led by Professor Sailong Xu (State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology), Professor Peng-Fei Wang (Center of Nanomaterials for Renewable Energy, State Key Laboratory of Electrical Insulation and Power Equipment, School of Electrical Engineering, Xi’an Jiaotong University) and Professor Bing Xiao (Center of Nanomaterials for Renewable Energy, State Key Laboratory of Electrical Insulation and Power Equipment, School of Electrical Engineering, Xi’an Jiaotong University).
See the article:
Elucidation of the sodium kinetics in layered P-type oxide cathodes
https://doi.org/10.1007/s11426-022-1364-1
Journal
Science China Chemistry