Manganese‐based metal oxide electrode materials are of great importance in electrochemical energy storage for their favorable redox behavior, low cost, and environmental friendliness. However, their storage capacity and cycle life in aqueous Na‐ion electrolytes is not satisfactory. Herein, the development of a biphase cobalt–manganese oxide (CoMnO) nanostructured electrode material is reported, comprised of a layered MnO₂⋅H₂O birnessite phase and a (Co_0.83Mn_0.13Va_0.04)_tetra(Co_0.38Mn_1.62)_octaO_3.72 (Va: vacancy; tetra: tetrahedral sites; octa: octahedral sites) spinel phase, verified by neutron total scattering and pair distribution function analyses. The biphase CoMnO material demonstrates an excellent storage capacity toward Na‐ions in an aqueous electrolyte (121 mA h g⁻¹ at a scan rate of 1 mV s⁻¹ in the half‐cell and 81 mA h g⁻¹ at a current density of 2 A g⁻¹ after 5000 cycles in full‐cells), as well as high rate performance (57 mA h g⁻¹ a rate of 360 C). Electrokinetic analysis and in situ X‐ray diffraction measurements further confirm that the synergistic interaction between the spinel and layered phases, as well as the vacancy of the tetrahedral sites of spinel phase, contribute to the improved capacity and rate performance of the CoMnO material by facilitating both diffusion‐limited redox and capacitive charge storage processes.

中文翻译：

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高容量和高倍率性能的双相钴锰氧化物用于钠离子电化学水储能

锰基金属氧化物电极材料因其良好的氧化还原性能，低成本和环境友好性而在电化学储能中非常重要。但是，它们在含水钠离子电解质中的储存容量和循环寿命并不令人满意。这里，双相钴-锰氧化物的发展（联合锰 O）纳米结构的电极材料据报道，由分层的MnO ₂ ⋅H ₂ ö水钠锰矿相和（共_0.83锰_0.13 Va的_0.04）_，四（共_0.38 Mn _1.62）_八O _3.72（Va：空位； tetra：四面体位点； octa：八面体位点）尖晶石相，通过中子总散射和成对分布函数分析进行验证。双相共锰 ö材料表现朝向钠离子的优异的储存容量在含水电解质（121毫安汞柱^-1以1毫伏s的扫描速率^-1在半电池和81毫安汞柱^-1以全电池5000次循环后的2 A g ^-1电流密度）和高倍率性能（57 mA hg ^-1360°C）。电动分析和原位X射线衍射测量结果进一步证实，尖晶石和层状相，以及尖晶石相的四面体位置的空位间的协同相互作用，有助于Co的改善的容量和倍率性能锰通过促进扩散受限的氧化还原和电容性电荷存储过程来形成材料。