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Bilayered Potassium Vanadate K 0.5 V 2 O 5 as Superior Cathode Material for Na‐Ion Batteries
Author(s) -
BaddourHadjean Rita,
Thanh Nguyen Huynh Le,
Batyrbekuly Daureen,
Bach Stéphane,
PereiraRamos JeanPierre
Publication year - 2019
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201902093
Subject(s) - vanadate , ion , raman spectroscopy , potassium , materials science , electrochemistry , cathode , prussian blue , vanadium , analytical chemistry (journal) , electrode , inorganic chemistry , chemistry , physics , organic chemistry , chromatography , optics , metallurgy
A bilayered potassium vanadate K 0.5 V 2 O 5 (KVO) is synthesized by a fast and facile synthesis route and evaluated as a positive electrode material for Na‐ion batteries. Half the potassium ions can be topotactically extracted from KVO through the first charge, allowing 1.14 Na + ions to be reversibly inserted. A good rate capability is also highlighted, with 160 mAh g −1 at C/10, 94 mAh g −1 at C/2, 73 mAh g −1 at 2C and excellent cycling stability with 152 mAh g −1 still available after 50 cycles at C/10. Ex situ X‐ray diffraction reveals weak and reversible structural changes resulting in soft breathing of the KVO host lattice upon Na extraction–insertion cycles (Δ V / V ≈3 %). A high structure stability upon cycling is also achieved, at both the long‐range order and atomic scale probed by Raman spectroscopy. This remarkable behavior is ascribed to the large interlayer spacing of KVO (≈9.5 Å) stabilized by pillar K ions, which is able to accommodate Na ions without any critical change to the structure. Kinetics measurements reveal a good Na diffusivity that is hardly affected upon discharge. This study opens an avenue for further exploration of potassium vanadates and other bronzes in the field of Na‐ion batteries.