Manganese-based layered oxides are currently of significant interest as cathode materials for sodium-ion batteries due to their low toxicity and high specific capacity. However, the practical applications are impeded ...
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Manganese-based layered oxides are currently of significant interest as cathode materials for sodium-ion batteries due to their low toxicity and high specific capacity. However, the practical applications are impeded by sluggish intrinsic Na+ migration and poor structure stability as a result of Jahn-Teller distortion and complicated phase transition. In this study, a high-entropy strategy is proposed to enhance the high-voltage capacity and cycling stability. The designed P2-Na0.67Mn0.6Cu0.08Ni0.09Fe0.18Ti0.05O2 achieves a deeply desodiation and delivers charging capacity of 158.1 mAh g-1 corresponding to 0.61 Na with a high initial Coulombic efficiency of 98.2 %. The charge compensation is attributed to the cationic and anionic redox reactions conjunctively. Moreover, the crystal structure is effectively stabilized, leading to a slight variation of lattice parameters. This research carries implications for the expedited development of low-cost, high-energy-density cathode materials for sodium-ion batteries. A high-entropy strategy is applied to design a new P2 phase cathode material for sodium-ion batteries, aiming to improve stability in deeply desodiated states. This material exhibits superior reversibility with 0.61 Na extracted, attributed to triggered lattice-oxygenredox reaction activity and facilitated Na+ migration. As a result, it demonstrates excellent initial Coulombic efficiency, high energy density, and lengthened cycling performance. image
lattice-oxygenredox in layered metal oxide cathodes offers a promising way to exploit high-energy density sodium-ion batteries. However, oxidation and reduction of lattice-oxygen are always asymmetric, showing poor r...
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lattice-oxygenredox in layered metal oxide cathodes offers a promising way to exploit high-energy density sodium-ion batteries. However, oxidation and reduction of lattice-oxygen are always asymmetric, showing poor reversibility upon charging and discharging due to the activated oxygen loss and subsequent structural rearrangement. Here, a layered Na0.7[Li0.2Mn0.7Co0.1]O2 (NLMCO) is developed by balancing lattice-oxygenactivity and reversibility, which can deliver a record energy density of 729.7 Wh kg-1, further exceeding the state-of-the-art Na0.75[Li0.25Mn0.75]O2 (NLMO, 638.4 Wh kg-1). In light of electron paramagnetic resonance spectroscopy, in situ differential electrochemical mass spectroscopy, and electrochemical testing results, the highly activated lattice-oxygen is effectively stabilized in NLMCO without oxygen molecule release while obvious oxygen release is detected in the highly activated NLMO. Benefiting from the enhanced transition metal-oxygen covalency and reduced band energy gap, the NLMCO electrode demonstrates simultaneously high lattice-oxygenactivity and reversibility, thus resulting in excellent rate and cycling performance, as well as ultra-high energy density. The findings highlight the critical association of energy density and lattice-oxygenredox reversibility, which will inspire more interest in anionic redox-based high-energy batteries. A record energy density of 729.7 Wh kg-1 is obtained in Na0.7[Li0.2Mn0.7Co0.1]O2 (NLMCO) for sodium-ion batteries by simultaneously balancing lattice-oxygenactivity and reversibility. Benefiting from the electronic structure and crystal structure modulation, NLMCO shows both high lattice-oxygenactivity and reversibility, ultimately leading to ultra-high energy density, as well as excellent rate and cycling ***
Manganese-based layered oxides are currently of significant interest as cathode materials for sodium-ion batteries due to their low toxicity and high specific capacity. However, the practical applications are impeded ...
详细信息
Manganese-based layered oxides are currently of significant interest as cathode materials for sodium-ion batteries due to their low toxicity and high specific capacity. However, the practical applications are impeded by sluggish intrinsic Na + migration and poor structure stability as a result of Jahn–Teller distortion and complicated phase transition. In this study, a high-entropy strategy is proposed to enhance the high-voltage capacity and cycling stability. The designed P2-Na 0.67 Mn 0.6 Cu 0.08 Ni 0.09 Fe 0.18 Ti 0.05 O 2 achieves a deeply desodiation and delivers charging capacity of 158.1 mAh g −1 corresponding to 0.61 Na with a high initial Coulombic efficiency of 98.2 %. The charge compensation is attributed to the cationic and anionic redox reactions conjunctively. Moreover, the crystal structure is effectively stabilized, leading to a slight variation of lattice parameters. This research carries implications for the expedited development of low-cost, high-energy-density cathode materials for sodium-ion batteries.
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