河北大学李战雨团队的一项最新研究利用表面氧化Mo₂C (MXene)原位合成MoO_3，用于在水基铝离子电池中实现稳定的近表面反应。这一研究成果于2024年10月21日发表在国际顶尖学术期刊《德国应用化学》上。

据介绍，三氧化钼（MoO₃）具有较高的理论容量，是一种很有前途的水基铝离子电池正极材料。然而，MoO₃在水电解质中存在反应产物易溶解、体积膨胀、电导率低等问题，严重限制了其在水基电池中的应用。

在这项工作中，该课题组通过在Mo₂C MXene层上原位生长MoO₃，有效地提高了电极的整体电导率。MXene能有效抑制MoO₃反应产物的溶解和结构损失。此外，Mo₂C和MoO₃的配位效应在MXene层叠板上实现了稳定的近表面反应，使得Mo₂C/MoO₃复合材料在0.4 A/g下循环200次后表现出优异的储铝性能（123.5 mAh/g）。

研究通过非原位表征阐明了H⁺/Al³⁺共插/提取的储能机理，并通过密度泛函理论计算验证了Mo₂C对MoO₃反应动力学的促进作用。这项工作为提高AAIB阴极的稳定性提供了新的见解，并扩展了钼基MXene在水基电池中的应用。

附：英文原文

Title: In Situ Synthesis of MoO 3  by Surface Oxidation of Mo 2 C (MXene) for Stable Near-Surface Reactions in Aqueous Aluminum-Ion Battery

Author: Yi Wang, Tianci Wu, Yong Lu, Wenming Zhang, Zhanyu Li

Issue&Volume: 2024-10-21

Abstract: Molybdenum trioxide (MoO3) is a promising positive electrode material for aqueous aluminum-ion batteries due to its high theoretical capacity. However, MoO3 faces several challenges in an aqueous electrolyte, such as easy dissolution of reaction products, volume expansion, and low conductivity, which severely limit its application in aqueous batteries. In this work, we effectively increased the overall conductivity of the electrode by in-situ growing MoO3 on the Mo2C MXene layer. MXene can effectively inhibit the dissolution and structural loss of MoO3 reaction products. Additionally, the coordination effect of Mo2C and MoO3 achieves a stable near-surface reaction on the MXene laminates, resulting in the Mo2C/MoO3 composite exhibiting excellent aluminum storage properties (123.5 mAh/g after 200 cycles at 0.4 A/g). The energy storage mechanism of H+/Al3+ co-insertion/extraction was elucidated through non-in-situ characterization, and the promotion effect of Mo2C on MoO3 reaction kinetics was verified by density functional theory calculations. This work provides new insights into improving the stability of AAIB cathodes and extends the application of Mo-based MXene in aqueous batteries.

DOI: 10.1002/anie.202416032

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202416032