Co2+/3+/4+-Regulated Electron State of Mn-O for Superb Aqueous Zinc-Manganese Oxide Batteries
Co2+/3+/4+-Regulated Electron State of Mn-O for Superb Aqueous Zinc-Manganese Oxide Batteries
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DOI：
10.1002/aenm.202003203
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发表时间：
2020-12-31
影响因子：
27.8
通讯作者：
Wang, Hao
中科院分区：
文献类型：
--
作者：
Ji, Jie;Wan, Houzhao;Wang, Hao
水性可充电锌锰电池因其成本低、能量密度高等优点而备受关注。然而，Mn(III)歧化和Jahn-Teller扭曲会导致Mn(II)的溶解和不可逆的相变，大大恶化了循环寿命。本文报道了一种具有高容量和可逆性的多价钴掺杂Mn3O4(Co-Mn3O4)，其原因在于掺杂钴的各种状态的多重作用。相变产物Delta-MnO2层之间的Co4+掺杂起到“结构支柱”的作用，层中Co4+的掺杂可以提高Mn4+的电导率并保持较高的比容量。更重要的是，Co离子(Co2+，Co3+)掺杂可以有效地抑制放电产物中的Jahn-Teller效应，促进离子扩散。利用X射线吸收光谱结果和密度泛函理论模拟，验证了掺杂钴的多重作用。Co-Mn3O4正极在100 mAg(-1)下的比容量为362mAHg(-1)，能量密度为463.1 Wh kg(-1)。在2.0Ag(-1)下循环1100次后，容量保持率达到80%。这项工作为设计高可逆性的锌离子电池正极材料提供了新的思路和方法。
Aqueous rechargeable Zn-MnOx batteries are very attractive due to their low-cost and high energy density. However, Mn(III) disproportionation and Jahn-Teller distortion can induce Mn(II) dissolution and irreversible phase changes, greatly deteriorating the cycling life. Herein, a multi-valence cobalt-doped Mn3O4 (Co-Mn3O4) with high capacity and reversibility, which lies in the multiple roles of the various states of doped cobalt, is reported. The Co2+ doping between the phase change product delta-MnO2 layer acts as a "structural pillar," and the Co4+ in the layer can increase the conductivity of Mn4+ and hold the high specific capacity. More importantly, Co ion (Co2+, Co3+) doping can effectively inhibit the Jahn-Teller effect in discharge products and promote ion diffusion. Using X-ray absorption spectra results and density functional theory modelling, the multiple roles of doped cobalt are verified. Specifically, the Co-Mn3O4 cathode shows high specific capacity of 362 mAh g(-1) and energy density of 463.1 Wh kg(-1) at 100 mA g(-1). After 1100 cycles at 2.0 A g(-1), the capacity retention rate reaches 80%. This work brings a new idea and approach to the design of highly reversible Mn-based oxides cathode materials for Zn-ion batteries.