X-ray imaging and micro-spectroscopy unravel the role of zincate and zinc oxide in the cycling of zinc anodes in mildly acidic aqueous electrolytes
X-ray imaging and micro-spectroscopy unravel the role of zincate and zinc oxide in the cycling of zinc anodes in mildly acidic aqueous electrolytes
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DOI：
10.1016/j.jpowsour.2022.231063
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发表时间：
2022-02-03
影响因子：
9.2
通讯作者：
Bozzini，Benedetto
中科院分区：
文献类型：
--
作者：
Kazemian，Majid;Rossi，Francesca;Bozzini，Benedetto
电池需求不断增长引发的可持续性、环境和安全问题正在推动后锂技术的研究。可充电锌电池是强有力的候选者，但由于对锌金属在放电-充电循环过程中的不稳定行为进行了广泛研究但知之甚少，因此仍然不实际可行。这一限制因素需要进行更基础的研究，并且本报告提供了由于弱酸性水性电解质中电化学循环而在电极/电解质界面处形成的锌基化合物的分子水平信息。结果是使用异位X射线吸收光谱显微镜图获得的，经过数学建模并辅以循环伏安法、对称电池测试和电子显微镜。我们已经确定了补给期间局部碱化产生的锌酸盐沉淀的作用，以及放电期间额外锌酸盐的形成和氧化锌的分解。该数学模型可以对观察到的形态化学变化进行透明的解释。这些过程的协同作用导致电化学定位效应，从而形成结构复杂且低电导率的 ZnO 基模板，这可能在驱动形状变化中发挥作用。
Sustainability, environmental and safety concerns raised by the increasing demand of batteries are driving research towards post-lithium technologies. Rechargeable Zn batteries are strong candidates, but still not practically viable, owing to the extensively studied, but poorly understood unstable behavior of Zn metal upon discharge-charge cycling. This limiting factor warrants more fundamental investigations and the present report provides the lacking molecular-level information on the Zn-based compounds forming at the electrode/electrolyte interface as a result of electrochemical cyclic in weakly acidic aqueous electrolyte. The results are obtained usingex situX-ray absorption spectromicroscopy maps, modelled mathematically and complemented with cyclic voltammetry, symmetric-cell tests and electron microscopy. We have identified the role of the zincate precipitation resulting from local alkalinization during recharge, combined with additional zincate formation and decomposition to zinc oxide during discharge. The mathematical model allowed a transparent interpretation of morphochemical changes observed. The synergy of these processes leads to electrochemical localization effects, resulting in the formation of a complexly structured and low conductive ZnO-based template, that might play a role in driving shape changes.