Jiang Yi, Deng Ya-Ping, Liang Ruilin, Fu Jing, Gao Rui, Luo Dan, Bai Zhengyu, Hu Yongfeng, Yu Aiping, Chen Zhongwei
Department of Chemical Engineering, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON, N2L 3G1, Canada.
School of Materials Science and Engineering, Tongji University Shanghai, 201804, Shanghai, China.
Nat Commun. 2020 Nov 17;11(1):5858. doi: 10.1038/s41467-020-19709-6.
The implementation of pristine metal-organic frameworks as air electrode may spark fresh vitality to rechargeable zinc-air batteries, but successful employment is rare due to the challenges in regulating their electronic states and structural porosity. Here we conquer these issues by incorporating ligand vacancies and hierarchical pores into cobalt-zinc heterometal imidazole frameworks. Systematic characterization and theoretical modeling disclose that the ligand editing eases surmountable energy barrier for *OH deprotonation by its efficacy to steer metal d-orbital electron occupancy. As a stride forward, the selected cobalt-zinc heterometallic alliance lifts the energy level of unsaturated d-orbitals and optimizes their adsorption/desorption process with oxygenated intermediates. With these merits, cobalt-zinc heterometal imidazole frameworks, as a conceptually unique electrode, empowers zinc-air battery with a discharge-charge voltage gap of 0.8 V and a cyclability of 1250 h at 15 mA cm, outperforming the noble-metal benchmarks.
将原始金属有机框架用作空气电极可能会为可充电锌空气电池注入新的活力，但由于在调节其电子态和结构孔隙率方面存在挑战，成功应用的情况很少见。在这里，我们通过将配体空位和分级孔隙引入钴锌异金属咪唑框架中来克服这些问题。系统的表征和理论建模表明，配体编辑通过引导金属d轨道电子占据的功效，降低了*OH去质子化的可克服能垒。进一步地，所选的钴锌异金属组合提高了不饱和d轨道的能级，并优化了它们与含氧中间体的吸附/解吸过程。凭借这些优点，钴锌异金属咪唑框架作为一种概念上独特的电极，赋予锌空气电池0.8 V的充放电电压间隙和在15 mA cm下1250 h的循环稳定性，优于贵金属基准。
