Department of Applied Chemistry and Bioengineering, Graduate School of Engineering, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan.
Phys Chem Chem Phys. 2020 Feb 28;22(8):4677-4684. doi: 10.1039/c9cp05829j. Epub 2020 Feb 14.
MgMnO having a spinel structure is a very attractive material for the positive electrode in Mg-ion batteries, since its reversible Mg extraction/insertion reaction can lead to a large reversible capacity. While the Mg extraction from MgMnO has been reported, the reaction mechanism remains unclear. In this paper, Mg ions were chemically extracted from MgMnO by acid digestion at various concentrations to produce MgMnO (0 < x < 1). The results showed that Mg extraction from MgMnO is a two-step two-phase reaction, via the intermediate MgMnO to the fully oxidised MnO. The kinetics of Mg extraction was clarified using acid digestion experiments of different durations, and the direct reaction pathway of MgMnO oxidation to λ-MnO was the fastest process. This may explain the difficulty in Mg extraction from MgMnO using electrochemical methods.
尖晶石结构的 MgMnO 是镁离子电池正极的一种极具吸引力的材料，因为其可逆的镁提取/插入反应可导致较大的可逆容量。尽管已经报道了从 MgMnO 中提取镁，但反应机制仍不清楚。在本文中，通过在不同浓度下的酸消解从 MgMnO 中化学提取镁，生成 MgMnO（0<x<1）。结果表明，从 MgMnO 中提取镁是一个两步两相反应，通过中间产物 MgMnO 到完全氧化的 MnO。通过不同持续时间的酸消解实验澄清了镁提取的动力学，并且 MgMnO 氧化为 λ-MnO 的直接反应途径是最快的过程。这可能解释了电化学方法从 MgMnO 中提取镁的困难。
