Xiao Bo, Cao Fuyong, Ying Tao, Wang Ziming, Zheng Dajiang, Zhang Wenchao, Song Guang-Ling
Center for Marine Materials Corrosion and Protection, College of Materials, Xiamen University, 422 South Siming Road, Xiamen 361005, China.
National Engineering Research Center of Light Alloy Net Forming, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
ACS Appl Mater Interfaces. 2021 Dec 15;13(49):58737-58745. doi: 10.1021/acsami.1c18913. Epub 2021 Dec 2.
Magnesium-air battery has been considered promising for electrochemical energy storage or as a conversion device due to its high theoretical energy density and low cost. However, the experimental energy density is far lower than the theoretical value due to the intense hydrogen evolution of the Mg anode upon discharging. Herein, we have successfully developed a novel MgZn (at. %) alloy via single-phase design. The as-prepared MgZn anode possesses a high discharge specific capacity of 1302 ± 70 mAh g and extraordinarily high efficiency of 94.8 ± 4.9%, which breaks the records of efficiency among all of the reported Mg anodes. The superior high efficiency is attributed to the anodic hydrogen evolution being inhibited by Zn alloying, which passivates the Mg matrix. The intermediate ion Mg produced during discharging is dramatically limited by the integrated passive film and is totally converted into Mg electrochemically through the film. Meanwhile, the uniform discharging products due to the homogeneous microstructure of MgZn co-contribute to the high efficiency. The design of the Mg-Zn alloy may open a new avenue for the development of Mg-air batteries.
镁空气电池因其高理论能量密度和低成本，在电化学储能或作为转换装置方面被认为具有广阔前景。然而，由于镁阳极在放电时强烈析氢，其实验能量密度远低于理论值。在此，我们通过单相设计成功开发了一种新型MgZn（原子百分比）合金。所制备的MgZn阳极具有1302±70 mAh g的高放电比容量和94.8±4.9%的极高效率，这打破了所有已报道镁阳极的效率记录。卓越的高效率归因于锌合金化抑制了阳极析氢，从而使镁基体钝化。放电过程中产生的中间离子镁被完整的钝化膜极大地限制，并通过该膜完全电化学转化为镁。同时，由于MgZn均匀的微观结构，均匀的放电产物也有助于实现高效率。Mg-Zn合金的设计可能为镁空气电池的发展开辟一条新途径。
