Sodium and Manganese Stoichiometry of P2-Type Na2/3 MnO2
| Autor: | Kuniko Chihara, Yoshiyuki Tahara, Kei Kubota, Shinichi Kumakura, Shinichi Komaba |
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| Rok vydání: | 2016 |
| Předmět: |
Phase transition
Jahn–Teller effect Sodium Inorganic chemistry chemistry.chemical_element 02 engineering and technology General Chemistry Manganese 010402 general chemistry 021001 nanoscience & nanotechnology Electrochemistry 01 natural sciences Redox Catalysis 0104 chemical sciences Crystallography chemistry Electrode 0210 nano-technology Stoichiometry |
| Zdroj: | Angewandte Chemie (International ed. in English). 55(41) |
| ISSN: | 1521-3773 |
| Popis: | To realize a reversible solid-state Mn(III/IV) redox couple in layered oxides, co-operative Jahn-Teller distortion (CJTD) of six-coordinate Mn(III) (t2g (3) -eg (1) ) is a key factor in terms of structural and physical properties. We develop a single-phase synthesis route for two polymorphs, namely distorted and undistorted P2-type Na2/3 MnO2 having different Mn stoichiometry, and investigate how the structural and stoichiometric difference influences electrochemical reaction. The distorted Na2/3 MnO2 delivers 216 mAh g(-1) as a 3 V class positive electrode, reaching 590 Wh (kg oxide)(-1) with excellent cycle stability in a non-aqueous Na cell and demonstrates better electrochemical behavior compared to undistorted Na2/3 MnO2 . Furthermore, reversible phase transitions correlated with CJTD are found upon (de)sodiation for distorted Na2/3 MnO2 , providing a new insight into utilization of the Mn(III/IV) redox couple for positive electrodes of Na-ion batteries. |
| Databáze: | OpenAIRE |
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