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Effects of Mn‐Doping on the Structural and Electrochemical Properties of Na 3 Ni 2 SbO 6 for Sodium‐Ion Battery.
Author(s) -
Kee Yongho,
Put Brecht,
Dimov Nikolay,
Staykov Aleksandar,
Okada Shigeto
Publication year - 2020
Publication title -
batteries and supercaps
Language(s) - English
Resource type - Journals
ISSN - 2566-6223
DOI - 10.1002/batt.201900166
Subject(s) - electrochemistry , doping , materials science , analytical chemistry (journal) , ion , cathode , sodium ion battery , formula unit , transition metal , phase (matter) , polarization (electrochemistry) , electrochemical kinetics , phase transition , sodium , inorganic chemistry , electrode , crystal structure , crystallography , chemistry , thermodynamics , faraday efficiency , biochemistry , optoelectronics , organic chemistry , chromatography , metallurgy , catalysis , physics
Abstract Recently, layered O′3‐Na 3 Ni 2 SbO 6 has been investigated as a unique cathode material for Na‐ion batteries due to the good electrochemical performance via O′3‐P′3 phase transitions in the voltage range between 2.0 and 4.0 V vs Na + /Na. However, at present it is not well understood whether transition metal doping of the pristine structure could improve the phase transition kinetics during charge/discharge. In this study, we synthesized Mn‐doped Na 3 Ni 2‐x Mn x SbO 6 ( x =0, 0.25, 0.5) layered oxides and investigated their feasibility as cathode materials for Na‐ion batteries using ex‐situ X‐ray diffraction (XRD) coupled with DFT calculations. The results show that light Mn doping ( x =0.25) energetically enhances the O′3‐P′3 phase transition kinetics with smaller unit‐cell‐volume changes. However, the heavily doped ( x =0.5) sample suffers from large polarization, which could be attributable to the reduced two‐phase reaction range and a large unit‐cell‐volume change upon sodium extraction.