Tuning Bulk O2 and Nonbonding Oxygen State for Reversible Anionic Redox Chemistry in P2-Layered Cathodes.
Angew Chem Int Ed Engl
; 61(16): e202115552, 2022 Apr 11.
Article
en En
| MEDLINE
| ID: mdl-35112438
ABSTRACT
Improving the reversibility of oxygen redox is quite significant for layered oxides cathodes in sodium-ion batteries. Herein, we for the first time simultaneously tune bulk O2 and nonbonding oxygen state for reversible oxygen redox chemistry in P2-Na0.67 Mn0.5 Fe0.5 O2 through a synergy of Li2 TiO3 coating and Li/Ti co-doping. O2- is oxidized to molecular O2 and peroxide (O2 )n- (n<2) during charging. Molecular O2 derived from transition metal (TM) migration is related to the superstructure ordering induced by Li doping. The synergy mechanism of Li2 TiO3 coating and Li/Ti co-doping on the two O-redox modes is revealed. Firstly, Li2 TiO3 coating restrains the surface O2 and inhibits O2 loss. Secondly, nonbonding Li-O-Na enhances the reversibility of O2- â(O2 )n- . Thirdly, Ti doping strengthens the TM-O bond which fixes lattice oxygen. The cationic redox reversibility is also enhanced by Li/Ti co-doping. The proposed insights into the oxygen redox reversibility are insightful for other oxide cathodes.
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01-internacional
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MEDLINE
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En
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Angew Chem Int Ed Engl
Año:
2022
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Article