Zong Hui, Liu Weicai, Li Mengshu, Gong Shijing, Yu Ke, Zhu Ziqiang
Key Laboratory of Polar Materials and Devices (MOE), Department of Electronics, East China Normal University, Shanghai 200241, China.
Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, People's Republic of China.
ACS Appl Mater Interfaces. 2022 Mar 2;14(8):10738-10746. doi: 10.1021/acsami.1c25264. Epub 2022 Feb 16.
The desirable air cathode in Zn-air batteries (ZABs) that can effectively balance oxygen evolution and oxygen reduction reactions not only needs to adjust the electronic structure of the catalyst but also needs a unique physical structure to cope with the complex gas-liquid environment. In this work, first-principles calculations were carried out to prove that oxygen-terminated NbCO MXene played an active role in enhancing the sluggish reaction of oxygen intermediates. NbCO MXene could also stimulate the spatial accumulation of discharge products, which was beneficial to improve the stability of secondary ZABs. Molecular dynamics simulation was used to show that the confinement effect of COF could effectively regulate the concentration of O on the surface of NbCO@COF, which was conducive to an efficient and durable reaction. COF-LZU1 was self-assembled on the interface of NbCO MXene (NbCO@COF) for the first time. The NbCO@COF electrode had excellent OER/ORR overpotentials with the potential difference (Δ) of 0.79 V. When applied to the configuration of ZABs, NbCO@COF showed a power density of 75 mW cm and favorable long-term charge/discharge stability, so it could be used as a potential candidate cathode for noble-metal-based catalysts. This idea of combining MXenes and COFs sheds some light on the design of ZABs.
锌空气电池（ZABs）中理想的空气阴极不仅需要调节催化剂的电子结构，还需要独特的物理结构来应对复杂的气液环境，以便有效地平衡析氧反应和氧还原反应。在这项工作中，通过第一性原理计算证明了氧端NbCO MXene在增强氧中间体的缓慢反应中发挥了积极作用。NbCO MXene还可以促进放电产物的空间积累，这有利于提高二次锌空气电池的稳定性。分子动力学模拟表明，COF的限域效应可以有效调节NbCO@COF表面O的浓度，有利于高效持久的反应。首次在NbCO MXene（NbCO@COF）界面上自组装了COF-LZU1。NbCO@COF电极具有优异的析氧反应/氧还原反应过电位，电位差（Δ）为0.79 V。当应用于锌空气电池配置时，NbCO@COF表现出75 mW cm的功率密度和良好的长期充放电稳定性，因此可作为基于贵金属的催化剂的潜在候选阴极。这种将MXenes和COFs结合的想法为锌空气电池的设计提供了一些启示。
