In this work, porous MgCo₂O₄ nanoflakes (MgCo₂O₄ NFs) and MgCo₂O₄ nanocubes (MgCo₂O₄ NCs) have been successfully synthesized through a simple hydrothermal method combined with a post calcination process of the precursor in air. The morphology of the MgCo₂O₄ samples can be easily tuned by changing the hydrothermal temperature and reaction time, respectively. The porous MgCo₂O₄ NFs with an average pore size of 12.5 nm had a BET specific surface area up to 64.9 m² g⁻¹, which was larger than that of MgCo₂O₄ NCs (19.8 m² g⁻¹). The MgCo₂O₄ NFs delivered a specific capacitance of 734.1 F g⁻¹ at 1 A g⁻¹ and exhibited a considerable rate performance with 74.0% capacitance retention at 12 A g⁻¹. About 94.2% of its original capacitance could be retained after 5000 charge–discharge cycles at a constant current density of 5 A g⁻¹. An asymmetric supercapacitor (ASC) was assembled by using MgCo₂O₄ NFs as the positive electrode and AC as the negative electrode, and the ASC had a wide operation voltage of 1.7 V and a high energy density of 33.0 W h kg⁻¹ at a power density of 859.6 W kg⁻¹. Such outstanding electrochemical performances make the MgCo₂O₄ NFs a promising candidate for supercapacitor applications. In addition, the simple and scalable synthesis method can be extended to the preparation of other metal oxide-based electrode materials.

中文翻译：

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多孔 MgCo2O4 纳米薄片的简便水热合成作为高性能不对称超级电容器的电极材料

在这项工作中，通过简单的水热法结合前驱体在空气中的后煅烧工艺，成功合成了多孔 MgCo ₂ O ₄纳米薄片（MgCo ₂ O ₄ NFs）和MgCo ₂ O ₄纳米立方体（MgCo ₂ O ₄ NCs）。 . MgCo ₂ O ₄样品的形态可以通过分别改变水热温度和反应时间来轻松调节。平均孔径为12.5 nm的多孔MgCo ₂ O ₄ NFs的BET比表面积高达64.9 m ² g ^-1, 大于 MgCo ₂ O ₄ NCs (19.8 m ² g ^-1 )。MgCo ₂ O ₄ NFs在 1 A g ^{-1下提供 734.1 F g -1的比电容，并在 12 A g -1}下表现出相当大的倍率性能和 74.0% 的电容保持率。^{在 5 A g -1}的恒定电流密度下，经过 5000 次充放电循环后，其原始电容的大约 94.2% 可以保持不变。使用 MgCo ₂ O _{4组装非对称超级电容器 (ASC)}NFs作为正极，AC作为负极，ASC具有1.7 V的宽工作电压和33.0 Wh kg -1 的高能量密度，^功率密度为859.6 W kg ^-1。如此出色的电化学性能使 MgCo ₂ O ₄ NFs 成为超级电容器应用的有希望的候选者。此外，简单且可扩展的合成方法可以扩展到其他金属氧化物基电极材料的制备。