Premium
Phase‐Pure P2‐Na 0.7(1− x ) [Li x Mn 1− x ]O δ as a Cathode Material for Na‐Ion Batteries
Author(s) -
Zhang Jiaolong,
Yu Denis Y. W.
Publication year - 2017
Publication title -
chemelectrochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 59
ISSN - 2196-0216
DOI - 10.1002/celc.201700054
Subject(s) - orthorhombic crystal system , materials science , intercalation (chemistry) , electrochemistry , annealing (glass) , cathode , analytical chemistry (journal) , phase (matter) , lithium (medication) , x ray crystallography , diffraction , crystallography , crystal structure , electrode , inorganic chemistry , chemistry , metallurgy , optics , medicine , physics , organic chemistry , chromatography , endocrinology
Na 0.7 MnO 2 is a potential high‐capacity cathode material for sodium‐ion batteries. Typical Na 0.7 MnO 2 material synthesized with quenching after annealing shows a P2 structure with orthorhombic distortion. However, the material is not stable when stored in ambient atmosphere and shows poor cycle performance during charge/discharge. In this study, we synthesized phase‐pure P2‐Na 0.7(1− x ) [Li x Mn 1− x ]O δ without orthorhombic distortion by adding Li into the precursor. We show that the material can be synthesized even with natural cooling, and is stable when exposed to air. Electrochemical tests and ex situ X‐ray diffraction studies reveal that the phase‐pure material exhibits fewer phase transitions and less structural degradation upon Na + de‐intercalation/intercalation, resulting in enhanced cycle performance. For example, Na 0.64 [Li 0.09 Mn 0.91 ]O 2.07 delivers an initial discharge capacity of 170.9 mAh g −1 with capacity retention of 61.1 % (104.4 mAh g −1 ) after 100 cycles. This is significantly better than the cycle performance of the distorted P2‐Na 0.7 MnO δ tested under the same conditions.